Eight free-ranging black spider monkeys (Ateles paniscus chamek) were immobilized with Telazol in Bolivia for the purpose of radio-collaring. During this procedure, the animals received complete medical examinations, and samples were collected for health analyses. Biochemical test results varied with the degree of condition of the animals, and a variety of physical abnormalities were found. Evidence of previous infections with Leptospira sp., encephalitis virus, and yellow fever virus was found. All findings contribute to establishing baseline health values for the species. The handling of primates for research projects provides a valuable opportunity to collect health-related data and samples that can contribute to wildlife management and conservation efforts. The capture and handling of free-ranging primates is always accompanied by risk of injury or mortality. It is ethically important to maximize the amount of information gathered during these procedures. Furthermore, sharing the undesirable impacts with the scientific community enables informed decisions to be made during future project development.