Aim of the work: To assess serum adiponectin in obese & non obese COPD during exacerbation and stable conditions and its relation to ventilatory functions. Subjects and Methods: The study was conducted on 40 male COPD patients during exacerbation and stable conditions with 15 age matched healthy control subjects. Patients and control were divided into non-obese and obese according to their body mass index. Subjects were submitted to full history taking, Complete physical examination, plain chest X-ray, Complete blood count, Erythrocyte sedimentation rate, Liver and kidney functions, Fasting and post prandial blood sugar,Ventilatory functions, and Venous blood samples for Adiponectin measurement. Results: There was Significant difference in serum adiponectin between exacerbated nonobese COPD and nonobese controls (P < 0.005) and significant difference in serum adiponectin between exacerbated obese COPD patients and obese controls (P < 0.05). Significant difference was observed in serum adiponectin between nonobese stable COPD and nonobese controls(P