Renal cell carcinoma is an uncommon tumor in children. For this reason, the clinical and pathologic features have not been fully appreciated. Fifteen cases from the files of the Armed Forces Institute of Pathology represent the largest series of this entity studied to date. When the tumor occurs in children it usually makes its appearance in mid-childhood and presents with hematuria and flank or abdominal pain. The presence of renal vascular invasion by tumor and absence of a fibrous pseudocapsule are the most ominous anatomic features of renal cell carcinoma in children.