In vitro fertilization and embryo transfer (IVF & ET) is widely used for the males with subnormal or abnormal semen quality, as this was recommended in view of the relatively small numbers of spermatozoa required for fertilization and subsequent pregnancies could be obtained. The aim of this study is to know how the various functional parameters of spermatozoa in semen analysis affect the outcome IVF. This study was carried out between 1988-1989, with male factor patients selected on the basis of the semen quality. The selection criteria was based upon the mean values of concentration,% motility and % normal morphology from at least two semen analysis. There is a significant decrease in the fertilization and embryo transfer rates in the study group compared with control group (35.9% vs. 68% and 48.6% vs. 85.5% respectively), however, there was no significant difference in the pregnancy or delivery rates (19.6% vs. 21.4% and 60.0% vs. 62.5% respectively) per embryo transfer cycles. Fertilization rate is variously affected by the type and degree of sperm defect. No pregnancy was occurred in triple defect group and asthenoteratospermia group. There is no significant increase in the abortion rate in the male factor group. Improvement have to be made with the fertilization rate, as the pregnancy rate per OPU cycle in male factor group is still lower than that of normal group (9.5% vs. 18.3%). In conclusion, IVF can be used as a treatment for male factor infertility and the preparation of the semen sample can be modified to improve sperm recovery and obtain fertilization from abnormal semen samples.