Varicocele is determined as dilatation of veins in the pampiniform plexus of the spermatic cord. Although various factors have been implicated in the pathophysiology of varicocele, the underlying aetiological cause is not fully understood. Endothelial dysfunction is a precursor of vascular pathologies that may develop gradually and a substantial inducer in atherosclerosis aetiology. Brachial artery flow-mediated dilatation (FMD) measurement with sensitive brachial artery ultrasonography for assessing endothelial function is the most common noninvasive method. Similarly, carotid intima-media thickness (CIMT), measured using noninvasive ultrasonographic methods, is a tool for evaluating subclinical atherosclerosis and gives information on early changes in the vessel wall structure. Totally, 128 patients met the criteria were evaluated in this study. FMD was significantly lower in the varicocele group compared with the control group (9.16 +/- 3.34 vs.7.96 +/- 1.88, p = .013). CIMT measurements were similar between the groups (p = .091). Multivariate logistic regression revealed that FMD was independently associated with varicocele [odds ratio (OR): 0.814; 95% confidence interval (CI): 0.697-0.950; p = .009]. We suggest that endothelial dysfunction may have a role in the varicocele. Therefore, we recommend that every patient with symptomatic varicocele should be evaluated and followed up regularly for cardiovascular pathologies.