The aim of this study was to investigate and compare histological characteristics of spermatic veins in patients with and without varicocele. Between February 2009 and July 2009, spermatic veins were obtained from 13 patients with varicocele. Microsurgical subinguinal low ligation was performed in all patients. Spermatic veins of patients without varicocele were obtained from 12 patients who underwent radical nephrectomy. Histologically, sections of veins were stained with haematoxylin and eosin. Mean tunica adventitia thickness size of the spermatic veins was 0.35 +/- 0.08 mm and 0.22 +/- 0.1 mm respectively in patients with varicocele and control group (P = 0.001). Similarly, mean tunica media thickness size of the spermatic veins was 0.25 +/- 0.05 mm and 0.09 +/- 0.04 mm respectively in patients with varicocele and control group (P < 0.001). No significant differences were detected regarding the tunica adventitia and tunica media thicknesses when patients with grade 2 varicocele were compared with patients with grade 3 varicocele (P > 0.05). No significant differences were detected between the tunica adventitia and tunica media thicknesses of patients with varicocele and sperm parameters (P > 0.05). Our study demonstrated that tunica adventitia and tunica media thicknesses seem to be increased in patients with varicocele compared with normal subjects.