Introduction: Chronic obstructive pulmonary disease (COPD) is a very complex systemic disease. Obesity and cachexia are the two extremes of metabolic disorders that are characteristic for COPD and associated with systemic inflammation. Adipose tissue produces and releases a proinflammatory and anti-inflammatory factors, including IL-6, TNF-α, leptin, adiponectin, which play an important role in the regulation of body composition. The aim of this study was to investigate differences in body composition (ratio of fat and lean mass) in patients with COPD depending on the severity of the disease and correlation with the concentration of humoral factors of inflammation (TNF-α, IL-6), adipokines (adiponectin, leptin), the status of vitamin D (25-OH D) and skeletal system. In the study 108 patients with COPD were included. The proportion of fat, lean mass and bone mineral density were determined by DEXA. Results: Thirty percent of COPD patients were found to be overweight and obese with a consequential effects on the characteristics of body composition (fat and lean tissues) and increased bone mass density. Hypovitaminosis D is present in almost all patients. Patients of both sexes with mild-stage COPD preserved lean body mass, while in men bone mass was also better. Leptin is positively correlated with body mass, parameters of body fat distribution and some densitometric parameters of bone mass in both sexes. In men a milder form of the disease is associated with better bone status and in women with the better lean mass. Only in men there is a negative correlation of adiponectin with BMI and indexes of body fat and hip bone status. The incidence of osteoporosis and osteopenia is generally identical in both sexes, but the prevalence of reduced bone mass in the lumbar spine area is significantly higher in women than in men. Conclusion: COPD is a condition that affects lungs and also other organ systems with serious effects on muscular and skeletal system due to systemic inflammatory conditions. Knowing and understanding the relations of the underlying disease and altered body composition of these patients is of great importance to medical care and prognosis of these patients.