This study was designed to identify the key components of physicians' attitudes toward managed care and develop a tool to assess these components. We developed a questionnaire based on physicians' reactions to managed care, as reflected in the published literature. We mailed this questionnaire to a sample of 753 community physicians in the greater Sacramento area. A factor analysis of these data (n = 315) identified five unifactorial scales, which we labeled managed care quality, need to adapt to managed care, cost-containment effectiveness of managed care, personal knowledge of managed care, and inevitability of managed care. Physicians were most negative about the quality of managed care and most in agreement about the need to adapt to it. Correlations among these five scales, while statistically significant, were modest in size, suggesting that these physicians were quite discriminating in their evaluations. In comparison with medical/surgical specialists, primary care physicians rated the quality of managed care, their knowledge of it, and the inevitability of a national transition to managed care more positively. These measures predicted the physicians' intentions to alter their medical behaviors to comply with managed care practices.