It has been recognized in recent years that renal cell carcinoma possesses a proximal convoluted tubules origin. In an attempt of further intensive evaluation we assayed 51 renal cell carcinomas and 38 additional normal kidney specimens with 4 kidney segment-specific antibodies (Uro-2/S4, Uro-5/T16, Uro-10/T43, Anti Tamm-Horsfall Protein) directed against the nephrotic cells by indirect immunohistological techniques. Consistently stable staining was developed in the tests. The results showed that the majority of renal clear cell carcinomas expressed nephrogenous properties of proximal convoluted tubules but in part also of distal tubules and collecting ducts. Granular cell carcinoma mostly demonstrated histogenic appearance of distal convoluted tubules.