Purpose of this study was to determine the impact of acrosine activity of ejaculated human spermatozoa on in vitro fertilization success . 71 samples picked up from routine screening for infertility and for IVF-ET procedures were divided into four groups and total acrosin activity of semen samples were estimated biochemically by a method of acrosin assay . Total acrosin levels were lower in subjects with oligospermia and teratospermia. The strongest positive correlation was determined between acrosin activity and fertilization rate amongst the all parameters. In conclusion, measurement of acrosin activity may be a valuable laboratory tool for assessing the sperm fertilization potential for normo and oligospermic subjects.