Differences in habits, customs and ethnic characteristics have provided important leads for the study of cancer in Indian Christians. It is a sign of the times that some of the social customs rigidly upheld by the older generations are rapidly giving way to "Modernism". An attempt has been made to examine the differences found in the site-specific cancer risks in this community in Bombay. An analysis of the data has been made by sex and age-adjusted and age-specific incidence rates. The common sites of cancer were found to vary greatly between the Christian and non-Christian populations of Greater Bombay. In Christian males, the lung appears to be at highest risk, followed by the stomach, oesophagus and larynx, whilst in non-Christian males the oesophagus is the commonest site followed by the lung, larynx and tongue. In females, breast and cervical cancers, which occupy the first and second ranks in Christians reverse their position in non-Christian women.