Cancer incidence and mortality in urban residents of New South Wales (NSW), 1987 to 1991, were analyzed according to socioeconomic status (SES) for males (m) and females (f). Incidence rates displaying a negative gradient with SES at P < 0.01 included: cancers of the mouth and pharynx (m), oesophagus (m), stomach (m,f), liver (m), pancreas (m), larynx (m), lung (m,f), cervix, kidney (m,f) and all cancers combined (m). Negative mortality gradients at P < 0.01 were observed for mouth and pharynx (m), stomach (m,f), rectum (m), liver (m), larynx (m), lung (m,f) and cervix, and all cancers (m,f). Those sites for which incidence showed a positive gradient with SES included: colon (m,f), melanoma (m,f), breast (f), prostate and testis. For cancer mortality for specific sites no significant (P < 0.01) positive gradients were observed, although for melanoma (m,f) a positive gradient at P < 0.05 was found. Mortality for all cancers considered together in both sexes was significantly higher in the low SES group compared to the high SES group. This is partly because the more-fatal cancers are more common in the lower SES groups. Diet, tobacco use, reproductive factors, occupational and sun exposures are likely to be associated with the patterns observed but are not investigated in this study. Variations in health care between SES groups may also be partly responsible for some of the differences.