OBJECTIVES. The objectives of this research are to examine if the sperm variables will be improved by the varicocelectomy, which of the variables will be improved, and in which way. STUDY DESIGN. Historical cohort study. PARTICIPANTS AND METHODS. 22 men were examined, aged between 15 and 46 years, who have been treated in the Department of Urology, CHC Osijek. They were included in this study because they underwent varicocelectomy. Spermiograms were compared (ejaculate volume, concentration, number, vitality, motility and morphology of spermatozoa) before and after surgical procedure. Spermigram diagnoses values were compared (normozoospermia, azoospermia, oligozoospermia, asthenozoospermia, oligoasthenozoospermia) before and after surgical procedure. Finally, all those variables were compared between two groups of patients (younger than 30 years and older than 30 years). RESULTS. Number, morphology, and motility, as well as concentration and vitality were significantly increased, which means that there is a connection between varicocelectomy and improvement in condition of sperm. There are significantly more motile and normally shaped spermatozoa in patients younger than 30 years after surgical procedure. There was no significant difference between them before the procedure, which can mean that there is a better response of a younger organism to the procedure, or that the disease lasted shorter. There are also patients with preoperative azoospermia, some of which had spermatozoa in the ejaculate after varicocelectomy. CONCLUSION. Number, morphology and motility of spermatozoa, as well as concentration and vitality are significantly increased after varicocelectomy, which are the main predictors of increased fertility after the procedure. There are significantly more motile and normally shaped spermatozoa after surgical procedure in patients younger than 30 years, than it is in patients older than 30 years; there was no significant difference between those two groups before varicocelectomy.