We performed DNA flow-cytometric analysis in three cases of angiomyolipoma of the kidney with lymph node involvement. The primary tumors of the kidneys and tumors in the lymph nodes of all patients contained diploid DNA. All three patients have been monitored for longer than 1 year and have no evidence of recurrence or metastasis. The lack of aneuploidy in both the kidney and the lymph nodes in our patients, although not excluding malignant neoplasia, supports the benign and multifocal nature of this lesion. Larger studies with long-term follow-up are reported to confirm this conclusion.