In this article we reviewed the pathophysiology, diagnosis and treatment of varicoceles. The etiology and pathogenesis of varicoceles cannot be explained by one theory. Valve dysfunction, ontogenetic collateral formation and the nutcracker phenomenon seem to act synergistically. Hyperthermia, elevated hydrostatic pressure and antisperm agents are suggested as possible causes for the pathophysiology how varicoceles induce infertility. However the combination of patient's lifestyle, genetic factors and the consequences of reflux into the pampiniform plexus are believed to contribute to the infertility. Although venography stays the gold standard, the combination of physical examination, color Doppler ultrasound and thermography has the highest sensitivity and specificity to diagnose a varicocele. Regarding infertility, we are still searching for strict criteria or grading, to decide which patients with a varicocele may or may not have benefit from treatment. Treatment of varicoceles can be performed by different open surgical or percutaneous techniques. Treatment of varicoceles for infertility or to prevent infertility remains controversial, because the majority of men with varicoceles are still fertile. At the moment, inguinal or subinguinal microscopic surgery gave the highest pregnancy rates, the lowest recurrence and lowest complication rates. But retrograde superselective glue embolization or sclerosing of the ISV are the best percutaneous alternative and can be performed on an outpatient basis under local anesthesia and with faster return to normal activities than surgery.