The willingness of nursing homes to accept any Medicare admissions (Medicare participation) and the number of patients they serve (Medicare utilization) affect the access of Medicare SNF patients to posthospital care. Characteristics of facilities, their market areas, and state Medicaid reimbursement were found to affect both participation and utilization. Most important, when Medicaid and private nursing home market conditions support high-intensity care, facilities are more likely to serve Medicare patients and admit more of them. SNFs in states that require Medicare certification are more likely to accept Medicare admissions, suggesting that the cost and effort of achieving certification are a barrier to service to Medicare SNF patients. For-profit facilities, hospital-based SNFs, and larger nursing homes have higher rates of participation and serve more Medicare patients when they serve any.