Purpose: With the increased need to establish primary care sites, we must identify the key characteristics of effective primary care training experiences. Methods: After completing a required year-long primary care experience, third-year medical students participated in focus groups (n= 17) and completed a Q-sort exercise with three sets of items: preceptor characteristics, site characteristics, and a combination of preceptor and site characteristics (n =59). Results: Thirty-eight concepts were identified by content analysis, which were grouped into six major categories: patients, preceptors' teaching behaviors, characteristics of office and staff, preceptors 'personal characteristics, programmatic issues, and educational opportunities. The focus groups clearly identified preceptor teaching characteristics (35%) as the major factor that determines a good primary care teaching site. Items with the highest rankings from the Q-sort exercises related to teaching characteristics of the preceptor. The preceptor's enthusiasm, genuine interest in students, and ability to involve the student in active learning experiences with increasing levels of student responsibility were rated high. Conclusions: The development of primary care experiences should focus on the selection and/or development of preceptors with the identified personal and teaching characteristics. Preceptor rather than site characteristics seem to make the vital difference in primary care educational experiences.