Androgenic control of epididymal function in reptiles has been studied in the skink, Mabuya carinata, by castration and androgen administration on histological, histochemical, and biochemical parameters. Castration of male skinks during the reproductive phase (Nov.-Dec.) leads to atrophy and regression of the epididymal epithelium with histochemically demonstrable loss of acid and alkaline phosphatase activities in the epithelium. Biochemically, reduction in DNA and protein contents and marked decrease in the activities of acid and alkaline phosphatases were observed. Administration of testosterone propionate (250 pg per animal on alternate days for 24 days) leads to hypertrophy of the epididymis, increased cell height, and histochemically demonstrable induction of acid and alkaline phosphatases in the epithelium. DNA and protein levels were also restored. In the quiescent phase (April-June) when the epididymis is fully regressed, the histological, histochemical and biochemical profile is comparable to that of castrated lizards in the reproductive phase. Administration of testosterone propionate to intact lizards leads to hypertrophy and stimulation of all the parameters, reminiscent of the condition in the reproductive phase. Alkaline phosphatase was found to be highly sensitive to androgenic deprivation and stimulation.