The purpose of this study is to assess the role of dynamic MR imaging in the evaluation of obstructive sleep apnea. In this prospective study, MRI was performed in 22 patients (eighteen male and four female, ranging in age from 26 to 70 years) suspected of having obstructive sleep aponea (OSA). 18 of them had a polysomnography study prior to MRI evaluation, which confirmed the presence of OSA. Positive cases were classified according to anatomic location and cause of narrowing. Patients with isolated retropalatal narrowing on MRI were advised uvulopalatopharyngoplasty (UPPP). Two patients had normal findings on MRI, 8 patients had retropalatal narrowing, five had retroglossal narrowing and seven had narrowing at multiple levels. All twenty-patients had collapse of lateral pharyngeal wall. Four patient with isolated retropalatal narrowing, who underwent UPPP after MRI evaluation were found to be cured on 6 month postoperative follow up.