In 1986, a diabetes control program was implemented in the Billings area of the IHS. Baseline health-care practices in the program were described using a structured audit. The program included adoption of the IHS Minimum Standards of Care for diabetes, technical assistance, and professional and patient education. A second audit was performed in 1988. Care practices improved significantly for all facilities in 7 of 10 parameters measured. Facilities that implemented key program activities showed more overall improvement in screening practices, education, and immunization than those that did not organize diabetes care. Factors associated with improved care practices include establishment of a coordinated, multidisciplinary diabetes team with regular meetings, acceptance of standards of care by the medical staff, use of flow sheets by multiple providers, and diabetes-related professional and patient education sessions.