Renal cell carcinoma is a group of malignancies arising from the epithelium of the renal tubules. The pattern of somatic mutations in kidney tumors has been extensively investigated. In the current 2004 WHO classification, the molecular background of a renal tumor has become, in addition to histopathology, a major criterion for tumor classification. The goal of this review is to discuss morphology and genetics of adult renal epithelial cancer included in the 2004 WHO classification and to mention renal tumor types, which are not considered in the current WHO classification. Further, pathologic considerations with clinical and prognostic implications are provided.