ACVIM stands for American College of Veterinary Medicine. This is a non-profit organization dedicated to improving the lives of animals and people through education, training and certification of specialists in veterinary internal medicine, discovery and dissemination of new medical knowledge, and increasing public awareness of advances in veterinary medical care. 

The ACVIM is the international certifying organization for veterinary specialists in cardiology, large animal internal medicine, neurology, oncology and small animal internal medicine.

An ACVIM Diplomate is a Board-certified Veterinary Specialist. In addition to completing veterinary school, a Board-certified Veterinary Specialist is similar to the human medical counterparts in that they have completed an internship and residency in their specialized field (an additional 3-5 years training). In addition to this extensive training, a Board-certified Veterinary Specialist must pass rigorous examinations to achieve Board certification from the ACVIM. Specialists bring a greater understanding in the area of internal medicine, cardiology, oncology, or neurology, and have a greater knowledge of the unusual, the uncommon, or rare in animals.