The results of selective phlebography of the spermatic vein in patients with primary sterility and suspected varicoceles are reported. In 60% of those examined there was left-sided, and in 8.8% right-sided, spermatic vein insufficiency or a varicocoele. The value of spermatic vein phlebography is borne out by the large number of anomalies of the venous system (67%) and by the finding of 82 left-sided varicoceles.