Background and Objective: COPD is one of the most common causes of death in the world. Metabolic syndrome is a pro-inflammatory and pro-coagulatory condition and a collection of cardiovascular factors, hypertension and dyslipidemia have increasing effects on morbidity and mortality and attacks of COPD disease. The aim of this study was to evaluate the relationship between metabolic syndrome and COPD. Materials and Methods: This case- control study included 76 COPD patients who had referrred to Valiasr Hospital of Zanjan and 76 non-COPD patients. Metabolic syndrome criteria was evaluated based on NCEP-ATP III and data was analyzed with T-test,Chi2 –test, Fisher exact test and logistic regression. SPSS 16 was used for data analysis. Results: The two groups had no differences in age and sex. The mean age in the case group was 63.3± 11.1 and in the control group was 60.6± 9.5. The age range of the participants was between 40 to 84 years. Prevalence of metabolic syndrome based on NCEP-ATP III, was 31.5% (24 persons) in the case group and 26.3% (20 persons) in the control group. With logistic regression analysis there was a significant difference between the two groups (p= 0.017). Occurrence of metabolic syndrome had no significant relationship with severity of COPD disease (p=0.27) and prevalence of this syndrome in COPD patients according to severity was: I: 37.5% II: 20% III: 45% and IV: 30%. Concerning the criteria of metabolic syndrome, hypertension had the most important relationship with COPD. Abdominal obesity, hypertension and HDL abnormality sequentially were the most common criteria of metabolic syndrome in patients with this disease. Also, this study pointed out that the risk of acquiring metabolic syndrome in females was more than males (P=0.01) Conclusion: Due to high prevalence of metabolic syndrome in COPD patients, some measures must be taken to prevent non-correctable metabolic indices. Rapid diagnosis and treatment of effective risk factors for COPD progression, specially in females should be considered.