The Authors report their experience on the treatment of simple voluminous renal cysts with an echo-guided puncture followed by a sclerosis, that is repeated thrice, with an endocavitary injection of pure alcohol. Since the fair results (94% of success) that were obtained after a mean follow-up of 16 months, the low invasivity of the method and the benignity of the disease, should propose the method itself as the first approach for the treatment of voluminous but not complicated renal cysts.