The gonadal veins are anatomically asymmetric and there are several anatomical variations involving them. During a renal vascular anatomy study through cadaver dissection, students of the School of Medical Science of Santa Casa of Sao Paulo, Brazil, found an anomalous drainage of the left spermatic vein. In the case presented here the right spermatic vein drains normally to the inferior vena cava, but the left spermatic vein penetrates in the inferior pole of the left kidney and there it tributes in a branch of the renal vein. According to the reviewed literature a case like this had never been reported. There was not any other abnormality in the renal vascular anatomy in this case. The gonadal vein, renal vein and the segments of inferior vena cava into which the gonadal vein drains have a common origin in the fetal subcardinal vein and or in its anastomosis with the supracardinal veins, which would justify the finding.