Abstract: Malnutrition is a common problem in moderate or severe Chronic Obstructive Pulmonary Disease (COPD) patients which affects body composition and food intake of these patients. In this study, the relationship of the stage of COPD with nutritional intake and body mass index in COPD patients were investigated and compared with healthy people and Dietary Reference Intake tables. A total of 93 COPD patients were referred by pulmonary physicians in Motahari and Faghihi medical centers. Pulmonary Function Test (PFT) was used in order to confirm the diagnosis of COPD and also categorize the patients into three categories (mild, moderate and sever). The control group consisted of 108 adults matched to the cases by age and gender. Anthropometric indices and physical activity and a 24 h dietary recall were recorded. All analyses were performed using the SPSS 14. All data presented as means (±SD). The mean intake of energy (p = 0.002), protein (p<0.001), fat (p = 0.007), vitamin C (p = 0.003), vitamin E (p<0.001), magnesium (p<0.001) and omega-3 (p<0.001) was significantly lower in COPD patients compared with controls. The mean BMI of the severe group was significantly lower than the controls (p = 0.016). The mean intake of energy, carbohydrate, fat, vitamin E, magnesium and omega-3 was significantly lower in both case and control groups compared to the RDA (p<0.001) for all of the mentioned nutrients). Vitamin C intake was lower than RDA in the case (p<0.001) and also in the control males (p<0.001). In COPD patients, there is a significant relationship between the stage of COPD and nutrients intake and their BMI.