Objective: To determine the clinical and evolutional peculiarities of community-acquired pneumonia in diabetics in comparison with non-diabetics. Materials & Methods: A study of 145 patients with community-acquired pneumonia (CAP) was performed. The patients were divided into two groups: the first group included 105 patients with CAP and diabetes mellitus (DM) and the second one included 40 CAP patients without DM. Results: The diabetic patients manifest protracted (15%, p<0,05) and frequently severe pneumonia evolution (46%, p<0,001) with the tendency of bilateral (20%) lung involvement. The clinical manifestations of CAP in patients with diabetes are subfebrility (65.4%), dry cough (38,3%), less typical or atypical lung consolidation (54.3%), tachypnoea and tachycardia. The mean duration of diabetes mellitus in our study was 7.9±0.8 years. Pneumonia was developed in patients manifesting diabetic microangiopathy and on the background of decompensated diabetes. The increased incidence of gram-negative pathogens and Staphylococcus aureus are etiological peculiarities of CAP in patients with diabetes mellitus. Conclusions: The association of CAP with diabetes mellitus leads to the reciprocal aggravation and more severe evolution of these diseases. Thus, the treatment must include both antibacterial therapy of pneumonia and glucose level correction.