Serum and urine samples from 15 male and 15 female captive reared young Aotus nancymae (night monkey, owl monkey or musmuki) were studied in order to determine normal physiological parameters of serum urea and creatinine, as well as urine composition, in animals reared under varying environmental, dietary and management conditions in the Peruvian Amazon. Serum urea and creatinine concentrations were found to be 42.15 ± 4.76 mg/dl and 1.35 ± 0.12 mg/dl. Urine, pH varied from 6.0 to 7.O, with specific weights between LOlO to 1.020. Negative reactions to protein, bilirubinogen, glucose, ketones and hidden blood were recorded, as well as a 0.2 negative reaction for urobilinogen.