Traumatic wounds and access to outdoor enclosures containing soil contribute to development of tetanus in nonhuman primates. A retrospective, matched case-control study was conducted at a primate center to evaluate these factors by analysis of medical records of animals sustaining traumatic injuries during a 3-yr study period. Thirty-one macaques with traumatic injuries and a clinical diagnosis of tetanus were selected as cases, and 62 macaques with traumatic injuries and no diagnosis of tetanus were selected as controls. For an animal with injuries to the digits, the odds of developing tetanus were 9.6 times those of a similar animal without injuries to the digits (Odds Ratio [OR] = 9.55, 95% CI = 1.56-58.59); with injuries to the tail, the odds of developing tetanus were 8.0 times those of a similar animal without injuries to the tail (OR = 7.95, 95% CI = 0.82-77.04); and with injuries in more than one location, the odds of developing tetanus were 8.5 times those for a similar animal with injuries in just one location (OR = 8.45, 95% CI = 1.01-70.46). A nonhuman primate with injuries to the leg was less likely to develop tetanus than a similar nonhuman primate without injuries to the leg (OR = 0.19, 95% CI = 0.03-1.2). Results indicated that wound location is associated with development of tetanus infection in rhesus macaques. Identification of high-risk trauma cases will allow better allocation of wound management and tetanus prophylaxis in institutions, especially in those housing nonhuman primates outdoors.