Background: The aim of the study has been to assess the usefulness of the Epworth Sleepiness Scale (ESS) and the Berlin Questionnaire (BQ) for obstructive sleep apnea syndrome (OSAS) screening. The capacity of both tests to discriminate between healthy individuals or with mild OSAS (apnea-hypopnea index (AHI) < 15/h) vs. patients with moderate or severe OSAS (AHI ≥ 15/h) was evaluated. Material and Methods: The study encompassed 223 patients with a suspicion of the OSAS. The ESS and BQ were completed by patients unassisted. Screening polysomnography was performed using the Porti SleepDoc. The OSAS was diagnosed when AHI ≥ 15/h or AHI ≥ 5/h with simultaneous occurrence of clinical symptoms. Results: The ESS score was found to be significantly higher in the study group compared to the control group (8.9±5.9 vs. 11.6±5.2 pt, p < 0.0001). Otherwise, there were no significant inter-group differences in the percentage of high-risk individuals according to the BQ (83.7% vs. 92.3%, p > 0.05). Sensitivity of the ESS and BQ was 53.2% and 93.1%, respectively while specificity was 58.8% and 16.2%, respectively. Poor correlation between the ESS score and AHI and apnea index were noticed (r = 0.22, p = 0.001 and r = 0.24, p < 0.001, respectively). Conclusions: Considering its low sensitivity, the ESS should not be used as a screening test for the OSAS diagnosis amongst candidates for drivers. The BQ is characterised by high sensitivity for the OSAS diagnosis with AHI ≥ 15/h, however, due to low specificity, the questionnaire may increase the number of healthy individuals referred for needless diagnostic procedures. Med Pr 2016;67(6):721–728