Between 1969 and 1991, 39 patients totalling 48 renal units with renal angiomyolipoma (RAMP) were diagnosed and treated in the Urology Service of the Hospital La Paz. In 5 patients, RAMP was part of a tuberous sclerosis, and was isolated in the remaining ones. RAMP was symptomatic in 32 cases (32/48 = 66.6%), 10 with Wundrelich's syndrome, and in 24 cases (24/48 = 50%) was larger than 4 cm. In the first cases of our series, clinical diagnosis through renal arteriography was achieved in 33% (5/14) cases; later, with the arrival of ultrasound and CAT, pre-operative diagnosis was possible in 88% (30/40) of cases. There was also 2 periods with regard to treatment, the initial one with predominance of radical surgery and the present one of observation and/or conservative surgery depending on size as well as signs and symptoms. Overall, 23 nephrectomies, 2 partial nephrectomies and 6 tumorectomies were performed, while there has been 17 cases (with no histological confirmation) treated with conservative approach and followed-up with ultrasound and CAT. With an average follow up of 8.4 years (range: 0.5-20 years), there has been no local or metastatic relapse of RAMP. There was one case of lymphatic affection which was explained as evidence of RAMP's multifocal condition and not as an indication of malignancy. In 3 patients, histological examination revealed coexistence of RAMP and renal carcinoma; 2 of these patients who underwent nephrectomy are free of disease; the third patient, treated with conservative surgery (tumorectomy), showed renal carcinoma relapsed after 2 years and had it removed. RAMP's incidence, histogenesis, diagnostic methods and treatment criteria are discussed.