Neutering and sterilising your pet in Spain

Key rules

• Cats: Cat owners must keep their cats sterilised unless they are registered breeders or a vet certifies a health reason against it.
• Dogs: There is no general national duty to sterilise a dog.
• Regions: Your region can add stricter rules than the national law, never weaker ones.
• Breeding: Only authorised, registered breeders may breed dogs or cats.
• Timing: When to operate is a health decision to agree with your vet.

Confirm the cat rule, breeding limits and any regional extras with your town hall or regional animal-welfare department before acting.

What the law requires

Cats must be sterilised. Dogs do not have to be. The national animal-welfare law, in force since 29 September 2023, puts its main sterilisation duty on cat owners. It does not set a general duty for dogs.

There are two exceptions for cats:

• You are a registered breeder.
• A vet certifies a health reason against sterilising your cat.

Cats that go outdoors are the main target of the rule. Check with your town hall before assuming an indoor cat is treated differently.

Breeding

Only authorised, registered breeders may breed dogs or cats. Registered breeders may keep entire (unsterilised) animals for breeding. Litter limits and the penalties for unregistered breeding are set in the law and its implementing rules. If you want to breed even once, register first.

What your region can add

The national law is the minimum. Regions have their own animal-protection laws and can be stricter, but not more lenient. Catalonia, Andalusia, Madrid, the Valencian Community and Galicia, for example, all require pet registration and regulate breeders and sales. Some also promote or subsidise sterilisation, including municipal capture-sterilise-return programmes for stray cat colonies.

The details differ by region and by town. Ask your town hall or regional animal-welfare department what applies where you live, and whether you can get subsidised sterilisation.

What is a health choice

For dogs, and for any cat with a vet's certificate, whether and when to operate is a decision with your vet. Timing depends on breed, size and sex. The timeline below sets out typical ages.

Benefits

• No unwanted litters.
• Lower risk of mammary tumours and pyometra (a womb infection) in females if done early.
• No testicular disease in males.

Risks

• Anaesthesia.
• Weight gain, so the diet must change afterwards.
• Urinary incontinence in some female dogs.
• Possible joint problems in large breeds if done too early.

Agree the timing and the aftercare with your vet. The checklist below covers what to ask.

Timeline and deadlines

• Sterilise a cat, before its first heat: at about 4 to 6 months old

• Sterilise a female dog before her first heat: at about 6 to 12 months old

• Sterilise a small-breed dog: at about 6 to 9 months old

• Sterilise a female dog after a heat instead: around 2 to 3 months after the heat

• Sterilise a large-breed dog, once it has finished growing: at 12 to 24 months old

Checklist

• Check that your cat is sterilised, unless you are a registered breeder or a vet certifies a health reason against it.

• Ask your vet for a written health certificate if your cat should not be sterilised for medical reasons.

• Ask your town hall or regional animal-welfare department whether your region adds sterilisation or breeding rules.

• Register as an authorised breeder before breeding any dog or cat.

• Ask your town hall about local capture-sterilise-return programmes or subsidised sterilisation.

• Agree the timing of the operation with your vet, based on your pet's breed, size and sex.

• Ask your vet about anaesthesia risks and how to adjust your pet's diet after the operation.

Frequently asked questions

Do I have to sterilise my dog in Spain?

No, dogs are not under a general national duty to be sterilised. Registered breeders may keep entire animals for breeding. Your region or town may add its own rules, so ask your town hall.

Can I keep an entire cat if it stays indoors?

Usually no: the national law expects owners to keep cats sterilised, whether or not they go outside. The exceptions are registered breeders and cats where a vet certifies a health reason against it. Ask your vet for that certificate if it applies.

Can my region make sterilisation rules stricter than the national ones?

Yes, regions can add stricter rules on sterilisation, breeding and registration, but never go below the national baseline. Some towns also run capture-sterilise-return programmes for stray cat colonies and may subsidise sterilisation. Ask your town hall what exists locally.

Is the timing of sterilisation a health choice?

Yes, the timing is a health choice you agree with your vet, depending on breed, size and sex. Large dogs are often left until growth has finished, while cats are usually done earlier. Ask your vet about the benefits and risks for your pet.