The structure of the tufted capuchin monkeys vas deferens was examined by light microscopy. Three main regions (proximal, distal and terminal) were morphologically identified. Each region could be readly distinguished through their gross histological characteristics. The epithelium of the vas consisting of four epithelial cell types: principal, basal, apical and dark cells. The three frequent cell types (principal, apical and basal), seem to be related to a cell cycle, in which the basal cells are the stem cells. The muscular coat comprise three muscular layers: (1) inner longitudinal, (2) middle circular, and (3) outer longitudinal. The muscular coat was relatively thicker than the others, probably in agreement to its peristaltic role, in the spermatic transport