Background The diagnosis of obstructive sleep apnea syndrome (OSAS) is based on nocturnal records: polysomnography or respiratory polygraphy. However, their high costs limit their use. Aim To examine the predictive value of three sleep questionnaires (STOP, STOP-Bang, Epworth Sleepiness Scale (ESS) in the screening of OSAS in Chilean adults. Material and Methods During the National Health Survey 2016/17, 205 adults aged 50.7 ± 15.0 years (46% males) living in the Metropolitan Region answered sleep questionnaires and underwent an ambulatory respiratory polygraphy. The sensitivity, specificity, positive and negative predictive values and receiver operating characteristic curves of sleep questionnaires were calculated. Results Fifty nine percent of participants had OSAS which was moderate to severe in 26%. The clinical variables associated with OSAS were age, male gender, hypertension, dyslipidemia, overweight, cervical and waist circumferences, history of regular snoring and witnessed apneas. Daytime somnolence, insomnia and unrefreshing sleep were not associated to OSAS risk. STOP, STOP-Bang and ESS questionnaires classified 64%, 71% and 12% of cases as high risk for OSAS, respectively. The STOP and STOP-Bang questionnaires had the highest sensitivity to predict OSAS (76% and 89%, respectively) while the ESS had the highest specificity (91%). Conclusions The sleep questionnaires allowed to identify the subjects at high risk for OSAS in this sample of adults from the Metropolitan Region.