The purpose of this study was to investigate the effect of water extract of Dioscoreae Rhizome on the reproduction activity of Wistar male rat. The group treated with 1.0 g/kg/day oral administrations of water extract of Dioscoreae Rhizoma (SK0l6) during 8 weeks was compared with the normal group. Sperm count, sperm motility, body weight, and testis weight were investigated in two groups. Sperm count. body weight, and testis weight of two groups did not show the significant difference. But sperm motility of the treated group was reduced significantly (the normal group: 56.43 %, SK0l6 group: 53.47 %, p < 0.05). According to the results, SK0l6 have no effects on sperm count, body weight. and testis weight but reduced sperm motility significantly.