The objective of the study was determination of bacterial etiologic factors, including antibiotic atypical pathogens, of community acquired pneumonia (CAP) in adults and of sensitivity of isolated strains. The examined group comprised 50 patients with clinical and x-ray image of pneumonia. Patients' expectoration sputum was analyzed. Amongst all isolated bacteria, the most frequent were Staphylococcus aureus - 17.9%, Haemophilus parainfluenzae - 12.5% and H. influenzae - 8.9%. Identification of Corynebacterium pseudodiphtheriticum in 8.9% of CAP cases drew our particular attention. Staphylococcus aureus was the least antibiotic sensitive microorganism. In the majority of patients (26: 52%), serologic markers of chlamydial infection were determined. Pneumonia often results from mixed typical and atypical flora infection. High percentage of atypical pathogens in the examined material suggests the necessity to administer intracellularly acting antibiotics.