Male genital tract inflammatory conditions may be associated with unexplained infertility. The presence of cytokine such as tumor necrosis factor-alpha (TNF-alpha) was reported in the semen of infertile men. However, the effect of these cytokines on human sperm function is still unclear. The purpose of this study was to investigate the in-vitro effects of TNF-alpha on human sperm motility with computer assisted sperm analysis. Washed sperm from 16 normal men were incubated without and with TNF-alpha(0.1, 10, 1000 ng/ml). The changes of parameters of sperm motility were recorded at different time intervals (0, 5, 24 hour). There was no significant change of parameters of sperm motility in the incubation with TNF-alpha. It is suggested that TNF-alpha alone does not interfere with the sperm motility and more studies are needed.