We studied community acquired pulmonary infections in general hospital. Forty-seven outpatients (group I) and 107 inpatients (group II) were analyzed respectively. The mean age of group I was 43.4 years old and that of group II was 57.4 years old. Significant underlying diseases were present in 45% of group I and 62% of group II. In group I, the underlying diseases were chronic respiratory diseases, and in group II, chronic respiratory diseases and other significant diseases such as diabetes mellitus, cardiovascular diseases, malnutrition or malignancy. All of group I and 81 cases of group II were pneumonia. Pleuritis with pneumonia (11), lung abscess or cavitary infection (11), and pyothorax (4) were included in group II. Etiologic organisms were determined in 48.6% of the cases in group I, and 44.0% in group II. Invasive methods such as transtracheal aspiration and percutaneous lung puncture aspiration were very useful for isolation of the pathogen. The pathogens isolated included H. influenzae (17), S. pneumoniae (10), M. pneumoniae (4), C. psittaci (4) in total cases. In group I, H. influenzae was mostly isolated and in group II, S. pneumoniae was mostly isolated and opportunistic pathogens were also isolated. The form of pneumococcal pneumonia was almost always focal pneumonia in this study. There were 8 fatalities (5.2%), all of which were very old or had other serious diseases.