Aim: In this study we investigated the increase in patient referral rates and diagnosis of obstructive sleep apnea syndrome (OSAS) by asking three cardinal symptoms. Methods: Patients who applied with different complaints to the family practice out-patient clinic between 04.01.2003 and 10.31.2003 (n=413) consisted the study group and they, along with their spouses, were asked about three cardinal symptoms of OSAS. Control group consisted 451 age and sex matched out-patients who had applied before the initiation of the study. Symptom positive patients were referred to an ear-nose-throat specialist and a sleep disorders specialist. Polysomnography was performed if indicated. Student-t test and chi-square test were used as appropriate. Results: There were no significant differences between groups about age, sex and body mass index (BMI) values. Patients diagnosed as OSAS were predominantly males. The mean BMI values for each group were classified as overweight. The rate of referral in control group was significantly lower than the study group. Out of the 413 patients three (%0.7) were diagnosed as OSAS, five (%1.2) were diagnosed as simple snoring. One of the three patients diagnosed as OSAS was female and the other two were male. Conclusions: It is our conclusion that all patients in primary care settings should be screened for cardinal symptoms of OSAS in order to prevent further complications and improve their quality of life. We started routine screening of all patients for OSAS by using three cardinal symptoms in our primary care out-patient clinic.