BACKGROUND: In South Korea, major health care problems have been occurred under the structural background that medical services are mainly provided by private medical institutions. Primary health care, which is very crucial in public health, has been overlooked, and is disorganized and fragmented. In the mean time, health cooperative movement was initiated by local residents and medical doctors to overcome health care problems in 1987. We conducted this study to evaluate the role of health cooperative clinics and obtain lessons for the future primary care policy. METHODS: During April to June in 2007, survey was performed by a trained interviewer at the waiting rooms of 3 health cooperative clinics, in the process of development of the Korean Primary Care Assessment Tool (KPCAT). The KPCAT consists of 5 domains (21 items): first contact (5), coordination function (3), comprehensiveness (4), family/community orientation (4), and personalized care (5). Subjects were patients (or guardians) who had visited their health cooperative clinics on six or more occasions over a period of more than 6 months. We compared primary care scores of each domain between members and non-members of health cooperative clinics by student t-test. Effect of having a membership on each primary care domains was examined by multiple regression analysis. RESULTS: Among the participants (N = 100), members of health cooperatives were 48, and non-members 52. Total average scores of 5 primary care domains of the KPCAT were 78.0 +/- 13.5 on 100 point scale. (82.0 +/- 13.1 in members, and 74.3 +/- 13.0 in nonmembers; P = 0.004) Among primary care domains, personalized care was the highest (91.4 +/- 11.0), and coordination function the lowest (61.0 +/- 33.1) in score. Significant differences between members and nonmembers were noted in coordination function (68.9 vs. 53.7, P = 0.021) and comprehensiveness (78.4 vs. 67.2, P = 0.008). These differences were continued after adjusting by multiple regression analysis for socio-demographic variables including age, sex, income, education, number of disease, and duration since the first visit. CONCLUSION: In the health cooperative clinics whose primary care performance has been considered exemplary in the context of health care in South Korea, primary care scores assessed by members were higher than those by non-members. The significant differences of scores in coordination function and comprehensiveness between members and nonmembers suggest that the future primary care policy should be focused to strengthen these two domains of primary care.