Abstract: This study compares diagnosis and commencement of treatment for cancer among persons with fully financed fee-for-service coverage, persons with copaid fee-for-service coverage, and persons in an HMO (health maintenance organization). A total of 242 subjects actively employed at the time of their diagnosis were interviewed, typically within six months of beginning cancer treatment. After sex, age, income, education, residence turban vs rural, and disease site and stage had been controlled, those who made copayments were found to have waited an average of 1.25 months longer (95 per ¢ confidence limit (cl) +/- .88) between initial suspicion or illness and obtaining a definitive diagnosis than those with full insurance coverage. Time from diagnosis until the beginning of treatment averaged .83 months longer (95 per ¢ cl +/- .41) for HMO members than those in fee-for-service. These relations were strongest in income categories equal to or exceeding $20,000 per year. (Am J Public Health 1987: 77:464-466.) [ABSTRACT FROM AUTHOR]