AimTo assess the adherence of physicians to the Medical-Care Guidelines for Malignant Breast Tumors in Mexico, before and after the allocation of federal subsidies from the Catastrophic Health Expenditure Fund (FPGC by its Spanish initials) to accredited hospitals, a strategy implemented with the view of offering free treatment to women with breast cancer (BC).Material and methodsBased on a cross-sectional design, we gathered information on 479 BC patients who had been attended to at in four FPGC-accredited hospitals. Analysis centered on those treated within either three years before or three years after the accreditation of their attending hospitals. The four hospitals analyzed were located in the North, South, West and Center of the country. Information on all medical procedures performed during treatment was drawn from hospital medical records. Information on the socio-demographic characteristics of the patients was obtained by means of face-to-face interviews conducted in their homes.ResultsAdherence of physicians to the Guidelines grew by 12.8 percent (from 43.4 to 56.2 percent) after FPGC accreditation (p<0.001) and varied according to the clinical stage of the disease, with much lower levels of adherence observed in the advanced stages (p<0.05).ConclusionsThe FPGC strategy increased the adherence of physicians to the Medical-Care Guidelines for Malignant Breast Tumors in Mexico.