The authors report 26 cases of renal angiomyolipomas (AML) detected in a three-years period (1983-85). In all cases echography, in 6 renal arteriography and in 13 CT were performed. The review of the pathway and of literature stress some new aspects in diagnostic problems of AML. The extensive use of diagnostic ultrasound shows an higher rate of tumors than in the pre-echographic period. Most of these lesions are asymptomatic and incidentally detected as small nodules. Ultrasound, combined with CT, can resolve the diagnostic dilemma of benign lesion. An echographic follow-up is sufficient to confirm this evaluation in typical cases. In large or bleeding tumors and when there is a prevalence of connective and/or muscular tissue, a diagnostic and ablative surgery is mandatory.