Varicocele occurs in approximately 15% to 20% of the general male population and it is the most common cause of poor semen production and decreased semen quality. It has been demonstrated that patients with varicocele have a significantly higher DNA fragmentation index (DFI) and spermatozoa with nuclear anomalies than healthy fertile men. Therefore, the aim of this study was to evaluate sperm chromatin integrity in these patients. Sixty men referring to the andrology laboratory were categorised into three different groups: 20 infertile men with varicocele, 20 infertile men with abnormal semen parameters and 20 fertile men who had normal spermatogram were considered as control group. Semen analysis was performed according to WHO criteria. To evaluate sperm chromatin quality and DNA integrity, after fixation of sperm smears, aniline blue, toluidine blue, chromomycin A3 and acridine orange staining were applied in three groups. The slides were analysed by light and fluorescent microscopy and to determine the percentage of mature or immature spermatozoa, 200 spermatozoa were counted in each slide. The results showed that the rates of aniline blue-reacted spermatozoa were significantly higher in infertile and varicocele patients than in the normal group (P < 0.001). In addition, with regard to chromomycin A3, acridine orange and toluidine blue staining, there was a significant difference between the three groups (P < 0.001). The results showed that the varicocele samples contain a higher proportion of spermatozoa with abnormal DNA and immature chromatin than those from fertile men as well as infertile men without varicocele.