Renal tumors in childhood consist of a diverse group of tumors ranging from the most common Wilms’ tumor, to the uncommon and often fatal rhabdoid tumor. Diagnosis is based on morphologic features and aided by ancillary techniques such as immunohistochemistry and cytogenetics. Molecular techniques have helped identify a group of pediatric renal cell carcinomas that have specific translocations, called translocation-associated carcinomas. Differential diagnosis of the various tumors is discussed. Pathogenesis and nephroblastomatosis, the precursor lesions of Wilms tumor, also are discussed briefly, as are the handling of these tumor specimens and prognostic factors.