The association of marital status and stage of diagnosis in cancer was examined for seven common disease sites. Data were drawn from the New York State Cancer Registry for Brooklyn residents diagnosed between 1978 and 1982. Married persons were found to have a better chance of early diagnosis only for cancers of the breast and prostate. When the analysis was stratified for race, this advantage was limited to whites. Married whites were 1.8 times more likely to be diagnosed with early prostatic cancer (p less than 0.01) and 1.2 times more likely to be diagnosed with early breast cancer (p less than 0.05). The earlier stage of diagnosis may be due to differences in a complex of social, economic, behavioral, and biological factors. These results suggest the need for additional educational and screening programs for the unmarried.