[영문]Background: It is widely acknowledged that many prescription drug errors occur in the ambulatory care setting and that they have serious quality of care implications. Previous research examining this issue has focused on hospitals and on individual-level factors. This study adopts an organizational perspective to assess the effects of organizational culture, organizational structure, and their fit (i.e., their congruence) on medication errors in medical group practices.Methodology/Approach: Variables that measure the organizational culture and structure were taken from two surveys of medical group practices in Minnesota in 2001. Medication errors data were obtained using a computerized drug utilization review system. Seventy-eight medical group practices were included in the analyses.Findings: Results revealed that the use of benchmarking and practice guidelines was associated with decreased error rates in group practices that encourage qqqquot;patient emphasisqqqquot; and qqqquot;collegiality.qqqquot; However, the relationship between information processing capacity and the cultural dimensions was not statistically significant.Practice Implications: The interaction between specific cultural traits and structural dimensions can help understand some of the relationships between organizational culture, structure, and medication errors. Organizational structures do not exist in a vacuum, but rather their effect on patient safety outcomes is qqqquot;moderatedqqqquot; by the organizational culture. The implications are that medical group practice administrators and medical directors have alternate ways to prevent or reduce medication errors and that they should be attentive to the cultures of their practices when considering those options