Bringing a Dog From Mexico to the US: CDC Form, Screwworm Certificate and Border Tips

Bringing a dog from Mexico to the United States is easier than bringing one from most of the world, but it is no longer the wave-through it was a few years ago. Mexico is not on the CDC list of high-risk countries for dog rabies, so there is no titer test, no government-endorsed rabies form and no quarantine. What catches people out now is a different agency entirely: the USDA treats Mexico as a screwworm-affected country, and every dog crossing north needs a screwworm freedom certificate dated within five days of the trip. Add the CDC Dog Import Form, a microchip and a minimum age of six months, and you have the whole federal checklist.

This guide covers that checklist in the order you will actually need it, then the parts that change by situation: driving across a land border, flying, adopting a rescue dog from a Mexican shelter, and bringing a cat. It is part of our inbound-to-the-US series alongside the Europe to the US hub. If you are going the other direction, see our guide to pet transport to Mexico.

The short version: four documents and one deadline

For a healthy adult pet dog that has lived only in Mexico or the US for the last six months, the federal paperwork comes down to four things:

• A microchip that a universal scanner can read. CDC uses it to match the dog to its paperwork.
• Proof the dog is at least six months old at the moment it enters the US. Younger puppies cannot enter, regardless of vaccines.
• A CDC Dog Import Form receipt, completed online, free, one per dog.
• A screwworm freedom certificate from a veterinarian authorized to sign it, issued after an inspection no more than five days before the dog crosses.

The deadline that matters is the five days. Everything else can be done weeks ahead, but the screwworm inspection has to be timed to the crossing. Book that vet appointment last, not first.

Why Mexico is on the easier CDC track

Since August 1, 2024, CDC sorts every dog by where it has been in the six months before arrival. Mexico does not appear on the CDC list of high-risk countries for dog rabies, so a dog that has only been in Mexico, the US or other low-risk countries follows the simplest path. According to the CDC page for dogs from rabies-free or low-risk countries, these dogs must be at least six months old, carry a microchip detectable by a universal scanner, appear healthy, and travel with a CDC Dog Import Form receipt. They can enter at any airport, seaport or land border crossing.

Two practical consequences follow. First, a dog on this track does not need the Certification of Foreign Rabies Vaccination and Microchip form that dogs from high-risk countries must carry, and it does not need a rabies titer. Second, the six-month look-back is strict. If your dog spent time in a high-risk country, for example Guatemala, Colombia or Peru, during the last six months, it is no longer a Mexico dog in CDC's eyes. It falls onto the high-risk path, which means a titer, an endorsed form and arrival at one of a handful of US airports. Our guide to importing a dog into the US walks through that harder path.

The CDC Dog Import Form, step by step

The form is online and takes most owners 15 to 20 minutes. You will need a clear photo of the dog, the microchip number, the dog's date of birth, your travel dates and your port of entry. A few details trip people up:

• One form per dog. Two dogs, two forms, two receipts.
• The receipt is what gets checked. Print it or have it ready on your phone. Border officers and airline agents ask for the receipt, not the confirmation email.
• It can be reused for six months on the low-risk track, as long as the dog does not visit a high-risk country in between. That matters for families who cross often, such as owners living in Baja and working in San Diego.
• Your port has to match. If your plans move from Tijuana to Nogales, update the form so the location matches where you actually cross.

The screwworm certificate: the step most guides still miss

New World screwworm is a fly whose larvae feed on living tissue. It spread north through Central America into Mexico, and the USDA now treats Mexico as a region where screwworm exists. The USDA page on bringing a pet dog into the United States says a dog from such a region may enter only with a certificate stating the dog was inspected for screwworm within five days before shipment and was found free of it, or was infested, held, treated and freed of it before leaving. Normally that certificate must be signed by a full-time salaried government veterinarian. For Mexico specifically, the USDA allows a clinical veterinarian who has been trained and authorized to sign on the government's behalf.

In practice that means you should ask your Mexican veterinarian, before you book, whether they are on the list of vets SENASICA has authorized for this certificate. Not every vet is. There is no single required USDA template, and the certification can be a standalone letter or part of a health certificate, but it must clearly state the inspection date and the finding. If your vet is not authorized, find one who is, ideally in the city you will leave from so the five-day window is easy to hit.

Cats are a different story. The USDA screwworm rule on this page applies to dogs, and CDC does not regulate pet cats beyond a general health check on arrival. Still, airlines and some US states may ask for a health certificate for a cat, so carry one.

Driving across: what happens at the land border

Most pets from Mexico come north by car, through crossings such as San Ysidro, Otay Mesa, Calexico, Nogales, El Paso, Laredo or Brownsville. Dogs on the low-risk track can use any land crossing. Expect the agriculture side of US Customs and Border Protection to ask for the CDC receipt and the screwworm certificate, look at the microchip number, and possibly scan the dog. Owners who cross often report that the depth of the check varies a lot from day to day, which is exactly why you should never rely on being waved through. A missing screwworm certificate is a reason to refuse entry.

Three habits make crossings smoother:

• Keep every document in one folder on the passenger seat, not in the trunk.
• Avoid peak hours in summer. Long idling lines in a hot car are a heat risk for the dog, not just an inconvenience. See our guide to pet transport in hot weather.
• Do not bring dog food with meat in it across. Agriculture rules on meat products are separate from the dog rules, and a bag of food can cost you time at secondary inspection.

Flying from Mexico into the US

The federal rules are the same whether you drive or fly, but airlines add their own layer. Most carriers on Mexico to US routes accept small dogs and cats in the cabin in an under-seat carrier, and some accept larger dogs as checked baggage or cargo, with seasonal heat embargoes that commonly apply in summer. Ask the airline three questions before you buy a ticket: does it carry pets on this exact flight, what are the crate rules, and which documents does it want to see at check-in. Many airlines ask for a health certificate even where the US government does not.

If the dog flies as cargo, a customs broker or the shipper usually handles the arrival side. If you are weighing cabin against cargo for a bigger dog, our comparison of pet cargo versus in-cabin travel covers the trade-offs.

Adopting a rescue dog from Mexico: different rules apply

Thousands of dogs are adopted every year from shelters and street-dog rescues in Mexico, and this is where the rules split. If the dog is coming to you as your own pet, the personal-pet rules above apply. If a rescue organization is importing the dog to rehome it for a fee, the import is commercial. The USDA page on importing dogs for resale or adoption says these dogs must be at least six months old, vaccinated against rabies at least 30 days before entry, vaccinated for distemper, hepatitis, parvovirus, parainfluenza and leptospirosis within 12 months, travel with an English-language health and rabies certificate, and travel under an import permit issued by APHIS Animal Care, with at least five business days allowed for processing.

So if a rescue tells you the dog can simply ride north with a volunteer, ask which route they are using and who holds the import permit. A legitimate rescue will answer clearly. If the answers are vague, or the rescue asks you to pay a large transport fee by wire before you have seen any paperwork, slow down and read our guide on how to avoid pet transport scams.

Puppies under six months

This is the single most common reason a Mexico move goes wrong. CDC's six-month minimum has no exception for puppies that are healthy, vaccinated or accompanied by their owner. A four-month-old puppy adopted in Puerto Vallarta cannot enter the US until it turns six months. If you are adopting young, plan to foster the puppy in Mexico until it is old enough, or arrange a reliable caregiver there, and use the waiting time to sort the microchip and paperwork.

Once you are across: state rules

Federal entry is not the last layer. Many US states require dogs to be vaccinated against rabies and some require a certificate of veterinary inspection for dogs entering the state, especially dogs that are being sold, adopted out or moved by a transporter. If you are driving deep into the US after crossing, check the rules for your destination state, and remember that a rabies vaccination given in Mexico is usually accepted for state purposes as long as the certificate is in order. Your local vet can give a US booster after arrival if you prefer a US-issued record.

What it typically costs

Driving your own dog across is the cheapest route by far. The CDC form is free, and the main cost is the vet visit for the screwworm certificate and any vaccines. Flying adds airline pet fees, and a professional shipper adds a coordination fee. The table below gives planning ranges, not quotes; confirm current prices with the vet, airline or shipper you actually use.

For a broader picture of what international moves cost, see our breakdown of international pet shipping costs.

A sensible order of operations

1. Confirm the dog will be at least six months old on the day you cross.
2. Check the microchip scans, or have one implanted.
3. Write down where the dog has been for the last six months. Any high-risk country changes everything.
4. If adopting from a rescue, confirm whether the import is personal or commercial, and who holds the APHIS permit.
5. Find a vet authorized to sign the screwworm certificate in your departure city and book the appointment for no more than five days before the crossing.
6. Complete the CDC Dog Import Form and save the receipt.
7. Check your airline's pet rules, or plan your crossing time and route if driving.
8. Check the rules in your destination US state.

Most families with a single adult dog and a car can handle this themselves. If you are moving several pets, a large dog by air, or a rescue dog with an uncertain history, a shipper can take the timing risk off your plate. You can compare options in our list of the best international pet transport companies.

Frequently asked questions

Booking the flight itself? Our guide to the Volaris pet policy explains its 6-month minimum age for dogs flying to the US, seat rules and fees.