Objective: to assess the accuracy of different endoscopic technique in diagbosis and detecting the site of collapse in OSAS patient. Material and methods: this was a prospective study including 32 patients (22 male and 10 females) the age mean is (43.41 year), the BMI mean is the (31.16 kg/m2) and AHI mean is (55.21 event/hour), suspected to have tongue base retrolingual collapse by using modified mallambati and cephalometry. All patients received Barbed suture suspension of the tongue base alone or with conjugation with Antrolateral advancement pharyngeoplasty for treatment. Results: there was no statistically significant difference between using muller maneuver and drug induced sleep enoscopy in diagnosis of site of collapse. Conclusion: there is no superiority for DISE over muller manoeuvre in diagnosis of the site of collapse in OSAS patients