Antegrade sclerotherapy is an established procedure for the treatment of varicocele. To avoid complications during the dissection of the pampiniform plexus, detailed knowledge of the angioarchitecture of the spermatic cord is recommended. One group of plexus veins is situated ventrolaterally and is surrounded by a yellowish fat which serves as a landmark. This vein group should be chosen for preparation. Phlebography of the internal testicular vein is mandatory. If arteries or major pelvic veins become visible while applying contrast media, sclerotherapy should not be performed. Paravasation of sclerosing agent has to be recognized and treated immediately to prevent deleterious effects.