A veterinarian (or veterinary surgeon) is a professional who diagnoses and treats animal disease, disorder, and injury. In colloquial terms, the name is usually shortened to "vet".

As a vet is likened to a doctor of humans, many countries impose rules on who can and may practice the diagnosis and treatment of diseases in animals. Basically, for someone to qualify as a vet, her or she must graduate with the degree intended for such medical practice in animals. In most nations, a degree holder must have also passed the licensure exam and is registered officially.

Most vets are employed in the clinical setting, practicing the treatment of animals directly. Some veterinarians are ascribed to general practice, while others choose to specialize in specific  groups of animals such as livestock, pets, zoo animals, among others. A vet may also choose to focus in a rigid medical discipline such as dermatology, surgery, or internal medicine.

Generally, vets are required to treat an ailing animal. However, what makes this task difficult is the fact that animals cannot articulate their conditions. For this, the vet has to rely on accounts from the owner (in case of pets), available medical history, observations, and data coming from diagnostic techniques such as X-rays, CT scans, blood tests, urinalysis, and the others.

After performing the appropriate medical methods on the animal patient, the vet is still tasked to conduct aftercare which includes prescribing medicines, further confinement, and more observations, among others.

Unlike in human medicine, vets are mostly allowed and will often consider the appropriateness of euthanasia or "mercy killing" if he deems that an animal will suffer in pain or with poor quality of life given a current condition. This action though, is covered by animal right codes and laws which vary from one country to another.

Majority of vets are in the private practice sector, treating animals upon heeding by owners.  Some choose to work in zoos where they get to check on the conditions of animals being displayed for public viewing regularly. Others work for pharmaceutical and research laboratories, and animal food companies, helping out in providing a quality life for animals via medicine, food, and supplements. There are also those who work for the government to lend a helping hand in several government thrusts such as anti-rabies campaigns. Still, several others prefer to work in colleges of veterinary medicine where they can impart their knowledge of the field to budding veterinarians.

 At present, the demand for the service offered by veterinarians is greatly increasing. This is brought about by the surge in the number of pet owners. It can also be attributed to the growing concern for animals which are considered vital in maintaining the balance of the ecosystem.