To define the possible role of the VHL gene in the development of sporadic renal cell carcinomas, 91 different parenchymal tumours of the kidney have been investigated for mutation of the VHL gene by single strand conformation polymorphism (SSCP) and/or heteroduplex (HD) techniques. Chromosome 3p deletion was detected in 98 per cent of non-papillary renal cell carcinomas and in 25 per cent of chromophobe renal cell carcinomas, In 22 of the 43 non-papillary renal cell carcinomas, abnormally migrating DNA bands were detected by SSCP and/or HD analysis, No mobility shift was seen in any of the 23 chromophobe renal cell carcinomas, In addition, 15 papillary renal cell tumours and ten renal oncocytomas, which are characterized by genetic changes other than loss of chromosome 3p sequences, were analysed for mutation of the VHL gene. None of these tumours showed abnormal migration patterns, The results indicate that mutation of the VHL gene is associated exclusively with the development of non-papillary renal cell carcinoma.