How to Introduce a New Pet to Your Home

A quiet room, a slow pace, and an early vet visit do most of the work when a new dog, cat, or small animal comes home. This plan fits adults and families bringing home a healthy adopted or purchased pet within days or weeks, with or without resident pets or young children. If your new pet is sick, injured, or has already bitten someone, call a vet or behaviorist first. This plan does not replace professional care.

Short answer

Give the new pet one quiet home-base room. Keep contact with people and other pets gradual, and never force it. Book a vet visit early, then open up the house one step at a time. The ASPCA's 3-3-3 guideline frames the timeline: about three days of feeling overwhelmed, three weeks of settling in, and three months of continued adjustment.

Plan on about three weeks of active steps, with adjustment continuing for about three months. Move to the next step when the animals are calm, not when the calendar says so. Some pets need longer. A shy cat in one ASPCA adopter story hid for several days, then quickly befriended the resident pets.

The plan at a glance

How to follow it

• Let the new pet set the pace. The ASPCA's advice for the first three days is to give the pet time and space to observe the home and its companions. It also says not to force interactions with people or other pets.
• Keep routines steady: feeding, walks or play, and bedtime at similar times each day.
• Stay calm and give clear, consistent direction, including boundaries.
• Do one new thing at a time. If a step goes badly, go back to the previous one.
• "Done" for each step means the animals look settled, not just that time has passed.

Tick off each step in the new pet introduction checklist as you go.

If the plan won't fit

• Short on time before pickup: Do only the essentials first: one room, secured windows and doors, water, a bed or crate, and a litter box for cats. Add toys and extras later.
• No spare room: A crate, soft bed, or playpen in a quiet corner can serve as the home base. Put gates across the doorways you want closed.
• Busy household: Keep visitors away for the first few days, and keep the new pet's space off the main traffic route.
• A step is taking much longer than expected: Stay at that step. The 3-3-3 guideline is a rough guide, not a deadline.
• Things escalate: Separate the animals with a door or gate and call a professional (see below).

Quick decision guide: which introduction path fits your pets

• No other pets, no young children: Follow the home-base steps, then widen access gradually.
• Resident dog: Use a gate or playpen for first meetings. Give your resident dog attention too. In one ASPCA adopter story, the dog who came first did not like sharing attention.
• Resident cat: Confirm the new cat's FIV and FeLV test results before any contact. See the species section below.
• Cat and dog together: Follow this plan, then see how to introduce a cat to a dog.
• Young children: An adult sets the rules and supervises every interaction.
• Small animal: Use the quiet-space and no-forcing rules, and ask a vet who treats that species about housing.

Before you bring them home: safe room and supply setup

The ASPCA's home preparation advice gives a short list:

• Dedicated space: a room, cozy crate, or soft bed where the pet can decompress.
• Safety: secure cords, windows, and doors, and remove chewable items. Use gates to limit access to certain areas.
• Plants: check that none are poisonous to pets, and choose pet-friendly houseplants for any room the new animal can reach.
• Basics: food and water bowls, plus a litter box for a cat.
• Fun items: a few toys. Cats also need scratching posts, and many like a perch. For a cat, double-sided sticky tape on furniture can discourage scratching.
• Resident pets' toys: store them separately until the animals adjust to one another.

For the home-base room, the ASPCA's moving guidance suggests favorite toys, treats, water and food bowls, and a litter box for cats. Once the pet seems comfortable, open other rooms gradually and keep some doors shut. If you later relocate a litter box, move it about one foot forward each day.

Body language: keep going, slow down, or separate

Keep going when the animals are settling:

• The new pet comes out of hiding on its own.
• A pet explores with head and tail up.
• Initial barking at a barrier fades. In one ASPCA staff account, the dogs barked at kittens through a playpen, then lost interest.
• Animals drift closer to each other while relaxing near you.

Slow down when a pet looks nervous or overwhelmed. That includes hiding, hesitating, or retreating. Go back to the previous step, shorten contact, and give more space.

Separate the animals right away if either one seems frightened or distressed, or if contact is getting more tense instead of calmer. Put a door or gate between them and return to home-base-only time. Don't physically pull animals apart with your hands. If anyone is hurt, see the next section.

When to stop and call a vet or behaviorist

Call your veterinarian promptly if:

• The new pet seems ill, stops eating or drinking, or changes behavior suddenly.
• A cat may have FIV. Have the cat examined and tested right away, and keep it indoors and away from other cats until diagnosed.
• A pet has a bite wound or injury from a fight. If a cat was bitten by a possibly rabid animal, the ASPCA says to give a rabies booster immediately and observe the cat for 45 days. Ask your vet to manage this.

Call a qualified behavior professional if:

• Aggression keeps happening, or interactions between pets or with people stay unsafe despite going back to earlier steps.
• Someone has been bitten.

While you wait for help, keep the animals fully separated.

Introducing a new pet to children and visitors

The same rule applies to people as to pets: don't force interactions. The ASPCA advises giving the new animal time and space to observe its surroundings.

• An adult stays present for all child-and-pet time and sets the rules.
• Let the pet come to people. Don't have children carry, corner, or chase it.
• Keep visitors out for the first few days, then bring them in one or two at a time while the pet stays calm.
• Show children where the pet's safe space is, and treat it as off-limits to them.
• If the pet is unsafe around children, separate them and call a behavior professional.

Differences by species and age

Dogs. Use a crate or bed in the home base, gates for limits, and early training. Puppies need extra care. The ASPCA says puppies should not be fully weaned before 8 weeks and are ideally placed at 10-12 weeks. A veterinarian at an ASPCA clinic warns that taking an unvaccinated puppy to the park puts it at risk. For house training, see potty training a puppy.

Cats. Provide a litter box, scratching posts, and a perch. Bring a cat home in a secure carrier. The ASPCA's NYC adoption center requires this. Cats joining a home with other cats need testing first. The ASPCA says every cat in a shared home should test negative for FIV, and any new cat should be tested for FeLV. It says introducing a new uninfected cat to a household with infected cats isn't advisable, even if the new cat is vaccinated for FeLV.

Small animals. Use the quiet space, no-forcing, and early-vet-visit rules. Ask a vet who sees that species before housing animals together.

Vaccines vary by place. One ASPCA clinic page lists puppy and kitten shots at 2, 3, and 4 months, and says rabies vaccination is required by state law. It suggests asking for 3-year vaccines. An older ASPCA flyer says pets are typically re-vaccinated annually and that New York City requires rabies shots at 3 months. Bring your pet's records and let your vet choose the schedule that fits your location and the animal.

Common mistakes and what to do instead

• Letting the new pet roam the whole house on day one. Start with the home base and open rooms gradually.
• Pushing a shy pet into the middle of the family. Let it watch from its space.
• Skipping the vet. Book the appointment in the first days.
• Leaving resident pets' toys out. Store them separately until the animals adjust.
• Ignoring the pet who was there first. Keep their routine and one-on-one time.

The plan schedule

Step 1: Set up the home base (before arrival)

Choose a quiet room. Add a bed or crate, bowls, toys, and a litter box for cats. Secure cords, windows, and doors, and remove chewable items.

Done right: The room is safe and closed off from other pets.

Step 2: Bring the pet home (arrival day)

Cats travel in a secure carrier. Go straight home and straight to the home base. Keep greetings short and calm.

Done right: The pet is in its room with the door closed and nobody crowding it.

Step 3: Let them decompress (days 1-3)

Keep a steady routine. Stay calm, positive, and patient. Give the pet time to observe without pressure.

Done right: The pet eats, rests, and explores its room.

Step 4: Book the vet visit and confirm cat test results (days 1-7)

Call to schedule the appointment. For cats, confirm the FIV and FeLV results before any contact with resident cats.

Done right: The appointment is booked and records are in hand.

Step 5: Start contact through a barrier (when the pet is out of hiding)

Use a gate or playpen so the animals can see and sniff each other. Keep each session short.

Done right: Reactions such as barking fade, and pets go back to their own business.

Step 6: Allow supervised time together (as barrier meetings stay calm)

Let the animals share a room only while you watch. Return the new pet to the home base afterward.

Done right: Both animals stay relaxed, and time together ends before tension builds.

Step 7: Open more rooms (weeks 1-3)

Add one room at a time and keep some doors shut. Move a cat's litter box about one foot per day if it needs a new spot.

Done right: The pet explores new areas without retreating.

Step 8: Build routine and training (week 3 onward)

Reward good behavior and keep boundaries consistent. Start basic training, such as coming when called. Keep bonding and learning the pet's likes and fears through month three.

Done right: Daily rhythms are predictable and the pet seeks you out.

Common mistakes

• Rushing to "make friends." A pet that is overwhelmed in the first days can't take in new animals or people. Forced contact adds stress, and the ASPCA says not to do it.
• Treating 3-3-3 as a deadline. It's a guideline, and individual pets settle at different speeds. Waiting costs little. A bad meeting can set you back.
• Mixing cats without test results. FIV and FeLV spread between cats, and a vaccinated cat may still be at risk around infected cats.
• Taking an unvaccinated puppy out to public places. Vaccines come first because exposure outdoors is a real disease risk.
• Letting chewables and cords stay within reach. A stressed new pet may chew or explore, and secured items protect both the pet and your belongings.

Safety and when to check with a professional

• Your vet is the right call for illness, injury, vaccine timing, and test results. A behavior professional is the right call for aggression that keeps happening or any unsafe interaction.
• Some household plants are poisonous to pets. The ASPCA's Animal Poison Control Center runs a 24-hour hotline staffed by licensed toxicologists, so keep the number handy.
• Don't put your hands between fighting animals. Separate them using doors and gates in advance.
• Keep animals apart whenever you can't supervise them.

Track your progress

Use the new pet introduction checklist to check off each step, note how each meeting went, and spot when it's time to slow down.

Frequently asked questions

How long until my new pet feels at home?

The ASPCA's 3-3-3 guideline points to three days to get past feeling overwhelmed, three weeks to settle, and three months to fully adjust. Treat that as a rough guide and follow your pet's behavior.

When should the new pet see a vet?

Book the appointment as soon as you bring the pet home. The ASPCA lists it among the first-three-weeks tasks. For a cat joining other cats, get FIV and FeLV results before contact.

Can I let my new pet explore the whole house right away?

No. Start with one home-base room, then open other rooms gradually while keeping some doors shut.

What if my resident pet and the new pet don't get along?

Separate them with a door or gate and go back to barrier-only contact. If the problem continues or anyone is hurt, call a vet to check for health causes and a qualified behaviorist for help with the aggression.

My new cat is hiding. Is that normal?

Hiding in the first days is common. Keep the room quiet, keep your routine steady, and don't pull the cat out. If the cat also stops eating or seems ill, call your vet.

Do I need to test a new cat before it meets my cats?

Yes. The ASPCA says all cats in a shared home should test negative for FIV, and that any new cat should be tested for FeLV. Ask the shelter or rescue for results, or have your vet test.

Related guides

• Pet Friendly Houseplants: Safe Picks for Cats and Dogs: Before or right after a new pet arrives, readers need to know which houseplants are safe for cats and dogs and which to remove.

Next steps

This week, set up the home-base room, book the vet visit, and then follow the New Pet Introduction Checklist as you work through each step.