Two cases of renal angiomyolipomas in female siblings associated with tuberous sclerosis were reported. The first case was a 47-year-old housewife who visited the hospital because of severe right flank pain. Bilateral renal angiomyolipomas and hemorrhage in the right angiomyolipoma were recognized by computerized tomography, ultrasonography and renal angiography. After 2 months she had another episode of left flank pain and was diagnosed to have hemorrhage in the left renal tumor. The pain remissed by conservative treatment. Bilateral nephrectomy and hemodialysis would be necessary if she were to have a third attack. The second case was her 36-year-old sister with the chief complaint of left flank pain and genital bleeding. CT and renal angiography suggested a large angiomyolipoma in her left kidney and a small one in her right kidney. Left nephrectomy, right partial nephrectomy and hysterectomy were performed to prevent intratumoral hemorrhage. The histopathological diagnosis was angiomyolipoma of kidneys, uterus and lymphnodes of right renal hilus. Although pre-operative differentiation of angiomyolipoma from renal cell carcinoma has been difficult, recently diagnosis has become possible by CT, ultra-sonography and angiography.