This chapter focuses on chimpanzees and macaques, many other species have been successfully trained for a variety of behaviors using positive reinforcement training (PRT). PRT is a form of operant conditioning in which an animal is rewarded for performing a desired behavior. It has become an established and integral component of successful behavioral management programs. The use of this training technique enhances nonhuman primates (NHP) welfare and facilitates health care by encouraging the animals to voluntarily participate in their own care. Veterinarians can closely examine NHPs in their home enclosures with the use of PRT techniques. PRT enhances the level of trust among the animals, trainers, and veterinarians. This high level of trust enables us to closely visualize the animals. NHPs can be trained using PRT techniques to voluntarily allow the collection of a variety of biological samples, which are crucial veterinary diagnostic tools.