There are many studies in the literature suggesting an acquired, apparently progressive infertility due to varicocele. In fact, varicocelectomy has become the most commonly performed male infertility surgery. Assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI) are also important for couples with male factor infertility associated with varicocele. Therefore, the aim of this study was to evaluate the effect of varicocelectomy on sperm quality and pregnancy rate with ICSI. Data were analyzed from 248 patients who had varicocele or underwent a previous varicocelectomy and were treated with ICSI between 2000 and 2008. Patients with varicocele were divided into two groups: men with clinical varicocele (group 1, n = 79) and men who underwent varicocelectomy before ICSI (group 2, n = 169). In all cases, female infertility was not detected. We evaluated and compared the two groups' semen characteristics as defined by the World Health Organization and Tygerberg's strict criteria: the female partner's age; the number of oocytes retrieved; and the fertilization, implantation, pregnancy, and miscarriage rates. We used the Wilcoxon signed rank test or the Mann-Whitney test for these analyses. No differences were detected in the age of the female partners between group 1 (33.0 ± 0.46 years) and group 2 (33.8 ± 0.38 years; P = .1872). Semen volume was higher in group 1 (3.3 ± 0.3 mL) than it was in group 2 (2.5 ± 0.14; P = .0043). No differences were detected between groups 1 and 2 with regard to sperm concentration (30.08 ± 4.01 million/mL and 24.1 ± 2.42 million/mL, respectively; P = .138), sperm motility (38.2% ± 2.69% and 38.7% ± 2.08%, respectively; P = .881), and morphology according to Tygerberg's strict criteria (2.6% ± 0.44% and 2.4% ± 0.37%, respectively; P = .7202). Also, no differences were detected in the number of oocytes retrieved between group 1 (14.8 ± 1.74) and group 2 (14.9 ± 1.04; P = .9515). The fertilization rate was higher in group 1 (73.2%) than it was in group 2 (64.9%; P = .0377); however, no differences were detected in the pregnancy rates (31.1% vs 30.9%; P = .9806), implantation rates (22.1% vs 17.3%; P = .5882), or miscarriage rates (21.7% vs 23.9%; P = .8401) between groups 1 and 2. Although a varicocelectomy should always be performed before assisted reproduction is pursued, this surgery does not increase pregnancy rates or decrease miscarriage rates following ICSI.