Obstructive sleep apnea is a common respiratory disorder that is still underdiagnosed in Morocco. This study aims to determine the prevalence of obstructive sleep apnea and its associated factors in primary healthcare. In this cross-sectional study, 815 adults aged 18 years and older consulting in the primary health care services in Marrakech, Morocco, were included. We evaluated the risk of obstructive sleep apnea syndrome using the modified STOP-BANG questionnaire. The prevalence of the high risk of obstructive sleep apnea in our sample is 24.8% (CI 95%: 21.7 - 27.6%). The variables independently associated with the high suspicion of obstructive sleep apnea were: gender male (p = 0.001), age ≥ 45 years (p = 0.001), high blood pressure (p = 0.005), hyperlipidemia (p = 0.042), daytime sleepiness (p = 0.003), snoring (p = 0.001), tiredness (p = 0.001) and mandibular retrognathia (p = 0.025). This survey revealed a significant prevalence of obstructive sleep apnea in Morocco. Therefore, we propose to generalize the screening of obstructive sleep apnea in hypertensive patients who report symptoms including daytime sleepiness, snoring, nocturnal choking, and tiredness that are unexplained by other known factors.