Mycoplasmas have long been suspected of contributing to involuntary infertility in couples. However considerable disagreement exits concerning the role of genital mycoplasma infection in human infertility. Several investigators have noted abnormalities in the semen analysis of men with positive mycoplasma cultures, and early epidemiologic studies indicated that Ureaplasma urealyticum was linked to human reproductive failure on the basis of higher frequencies of isolation from infertile versus fertile couples and successful pregnancies in infertile couples after doxycycline therapy. However, subsequent investigators have questioned these findings because there are many studies in which treatment for mycoplasma in the male or female did not demonstrate an improved pregnancy rate, and semen samples from unexplained infertile men containing ureaplasmas have not revealed poorer motility, fewer spermatozoa and more aberrant forms. The objective of this study were to investigate the incidence rate of mycoplasma in semen and to investigate whether the presence of mycoplasma in semen makes significant difference to the semen volume, sperm motility and sperm counts. The results were that the rate of isolation of mycoplasma species was 70.3%. Semen volume is $2.84{pm}1.01ml$ for culture negative and $3.15{pm}1.42ml$ for culture positive group. Sperm motility is $46.23{pm}15.80%$ for culture negative and $50.09{pm}15.69%$ for culture positive group, and sperm count is $95.47{pm}47.14({ imes}(P)10^6/ml)$ for culture negative and $86.73{pm}47.59({ imes}10^6/ml)$ for culture positive group. In conclusion, we suggest that the presence of mycoplasma in semen makes no significant differences to the sperm parameters.