Urban safety net providers are under pressure to improve primary care productivity. In a survey of ambulatory care facilities in New York City, productivity (measured as the number of primary care visits per provider hour) increases with exam rooms per physician but has no association with computerized information systems or tightly controlled reimbursement. Also, sample facilities rely heavily on residents, which makes these facilities sensitive to medical education policies and raises questions about quality of care for the poor. We conclude that urban safety net providers will have difficulty making the productivity improvements demanded by a more competitive health system.