P-glycoprotein and epidermal growth factor (EGF) receptor expression were surveyed immunohistochemically in the tissue of urogenital carcinomas including 12 renal cell carcinomas, 9 bladder transitional cell carcinomas, 2 prostate adenocarcinomas and 1 penile squamous cell carcinoma. Three bladder carcinomas and the penile carcinoma were following initial chemotherapy at the time of relapse. P-glycoprotein expression was detected in 3 of 12 renal cell carcinomas and in all recurrent carcinomas. EGF receptor was not detected in any of the specimens.