Objectives: The aim of this study was to examine the body composition of patients diagnosed with COPD, and to research the relationship between the fat-free mass index and the body mass index in COPD patients. The secondary objective was to examine whether there is a difference between groups of patients of different nutritional status in terms of severity of airway obstruction, symptoms, frequency of exacerbations, and pack-years. Study design: cross-sectional research Subjects and methods: The study included 40 outpatients of Clinical Hospital Center Osijek diagnosed with COPD. All patients had anamnestic data, spirometry done and symptom assessment questionnaire (CAT and mMRC) fulfilled. Body composition was measured by bioelectrical impedance method. Results: Significant positive correlation of BMI with FFM (P < 0.001) and with FFMI (P < 0,001) was observed. There were 30 (75 %) patients with normal nutritional status, 4 (10 %) patients with mild malnutrition, 3 (8 %) patients were sarcopenic, and 3 (8 %) patients were cachectic. Patients with normal nutritional status had significantly fewer exacerbations in the last 12 months compared to the malnourished patients (Fisher’s exact test, P = 0,03). No statistically significant difference was observed between groups of patients of different nutritional status in terms of the severity of airway obstruction, symptoms, and pack-years. Conclusion: A significant proportion of patients with COPD had decreased muscle mass which is a poor prognostic sign. In our study, there were 8 % of patients with sarcopenia, representing patients who are not recognized in clinical practice but they need nutritional support. Patients with poorer nutritional status had a higher number of exacerbations which also adversely affects the prognosis of the disease.