Countries with historically unlimited patient choice of medical provider, such as Korea, have been promoting rational health care pathways. Factors related to the length of doctor-patient relationship (DPR) for enhancing primary care in those countries should be studied. Participants were patients who had visited their family practices on six or more occasions over a period of more than 6 months. Five domains (21 items) of the Korean Primary Care Assessment Tool (first contact, coordination function, comprehensiveness, family/community orientation, and personalized care) and general questions were administered in the waiting rooms. From seven practices, the response rate was 83.7% (495/591). The older the age, the lower the income, the shorter the duration of education, the more the number of diseases the patients had, and in provincial cities rather than in Seoul, the longer length of DPR ( ≥ 4 yr) was shown. The long-term DPR was associated with total primary care quality score (upper [ ≥ 71.4] vs lower [ < 71.4], OR, 1.74; 95% CI, 1.10-2.76), especially with coordination function (OR, 1.01; 95% CI, 1.00-1.02), being adjusted for confounding variables. Strengthening the coordination function may have to be the first consideration in primary care policy in countries like Korea.