The genital swelling patterns and birth records of female mandrills housed at the Tulsa Zoo between 1979 and 1992 were examined to determine various reproductive parameters. Mean age at first adolescent genital swelling was 2.7 years (sd = .55), first adult swelling was 3.7 years (sd = .64), and first conception was 5.1 years (sd = 1.30). Genital swelling cycle duration averaged 39.6 days (n = 33 cycles), with the swelling phase averaging 19.5 days (n = 51 cycles). There was no interindividual difference in cycle length (F = 1.26, P = .31) or swelling duration (F = 0.65, P = .58), nor was there a difference in cycle length (F = 0.47, P = .50) or swelling duration (F = 1.27, P = .27) before and after first parturition. Duration of gestation was estimated to be 165.9 days (sd = 3.3; n = 17 pregnancies). Lactational anestrus averaged 10.1 months, whereas mean interbirth interval was 17.9 months (n = 11). There was a significant negative correlation between age of the mother and interbirth interval (r = −;0.648, P = .03). Data presented in this report provide a comprehensive profile of reproductive parameters for zoo-housed mandrills, which may aid other facilities in the reproductive management of their captive groups. © 1995 Wiley-Liss, Inc.