Effect of Weight Reduction and Exercise Program on Patients with Obstructive Sleep Apnea Abstract: Background: Obesity is the most important risk factor for obstructive sleep apnea (OSA). Aim: The aim of the study was to evaluate the effectiveness of weight reduction and exercise program on patients with OSA at a university hospitals in Egypt. Subjects and methods: Research design: A quasi experimental one group pre/post test design was utilized to achieve the aim of the study. Study Setting: The study was conducted in Sleeping Disorders Unit of Chest Department, Zagazig University Hospitals in Egypt. Sample: A purposive sample included 30 patients with a confirmed diagnosis of OSA were recruited in this study. The program implemented through 10 months from September 2017 to June 2018. Tools of data collection: Five tools of data collection were used: (1) A structured interview questionnaire. (2) Berlin questionnaire. (3) Epworth sleepiness scale. (4) Questionnaire of sleep apnea, and (5) Questionnaire to assess sleep disturbance symptoms associated with obesity. Results: There was a significant reduction in weight through decreasing in BMI, neck circumference, and waist circumference with mean±SD 103.87±21.11, 35.27±7.66, 36.67±4.85, 112.83±16.51 respectively after intervention of program that reflected then on decreasing sleep disturbance symptoms associated with obesity. The sleep efficiency increased after intervention of program with mean±SD 88.32 ±8.50 through increasing in Base SPO2% (oxygen saturation during daytime) and mini SPO2% and reduction in sum of desaturation (difference between sleep and awake), snoring index, AHI (apnea-hypopnea index). In addition, there was a reduction in daytime and nocturnal symptoms of sleep disorder breathing after intervention of program. Conclusion: Hence, it can be concluded that the application of a balanced and low calorie dietary intake and regular exercise training for upper airway was effective on improving severity of OSA. Keywords: Exercise program, Obstructive Sleep Apnea, Weight reduction