International variations in the incidence of testis and prostate cancer are well established. Data from the USA have also shown differences between White and Black men; however, there has been little work on ethnicity and cancer incidence in the UK, due to incomplete ethnicity information in cancer registries. The Hospital Episode Statistics (HES) dataset has more complete information on self-assigned ethnicity for inpatients of English NHS hospitals. Data on 194 590 male patients resident in South East England diagnosed with cancer between 1998 and 2003 were extracted from the Thames Cancer Registry (TCR). Of these, ethnicity information from HES was obtained for 123 507 (63%), ethnicity information from TCR was available for a further 5909 (3%), and no ethnicity was available for 65 174 (33%). Compared with 'All White' men, testis cancer incidence was significantly lower in Indian, Pakistani, Bangladeshi, Other Asian, Black Caribbean, Black African, Other Black and Chinese men. Prostate cancer incidence was significantly increased in Black Caribbean, Black African, Other Black, Indian, Pakistani, Mixed White and Black Caribbean and Mixed White and Black African groups compared with 'All White' men. Bangladeshi and Chinese men had a significantly decreased incidence of prostate cancer. The incidence of prostate cancer in Indian and Pakistani men showed convergence towards the rates in the white population, suggesting the existence of modifiable risk factors in these men. Most other variations in these data are consistent with international comparisons, and indicate that genetic variations in susceptibility are very influential.