Second primary cancers found among whites and blacks with initial cancer of the digestive organs were reported based on data from the Charity Hospital Tumor Registry. Observed second primary cancers were compared to expected numbers to obtain a direct estimate of risk. Both white and black men had about a twofold risk of developing a second cancer. For white men, the excess was limited to a subsequent skin cancer, but this finding was probably an artifact of reporting and lacked biologic significance. Among women, both white and black, large excesses of invasive cancer of the cervix and ovary were found after an initial cancer of the large intestine and anorectum was discovered. No excess of breast cancer was found.