We describe the impact of community health workers (CHWs) providing community-based support services to enrollees who are high consumers of health resources in a Medicaid managed care system. We conducted a retrospective study on a sample of 448 enrollees who were assigned to field-based CHWs in 11 of New Mexico's 33 counties. The CHWs provided patients education, advocacy and social support for a period up to 6 months. Data was collected on services provided, and community resources accessed. Utilization and payments in the emergency department, inpatient service, non-narcotic and narcotic prescriptions as well as outpatient primary care and specialty care were collected on each patient for a 6 month period before, for 6 months during and for 6 months after the intervention. For comparison, data was collected on another group of 448 enrollees who were also high consumers of health resources but who did not receive CHW intervention. For all measures, there was a significant reduction in both numbers of claims and payments after the community health worker intervention. Costs also declined in the non-CHW group on all measures, but to a more modest degree, with a greater reduction than in the CHW group in use of ambulatory services. The incorporation of field-based, community health workers as part of Medicaid managed care to provide supportive services to high resource-consuming enrollees can improve access to preventive and social services and may reduce resource utilization and cost.