We tried to verify whether the currently employed diagnosis and treatment of community-acquired pneumonia in children were appropriate. For this purpose, we created tentative criteria for the classification of pediatric community-acquired pneumonia. We classified the community-acquired pneumonia into ten categories: (1) bacterial, (2) concomitant viral-bacterial, (3) viral, (4) mycoplasmal, (5) concomitant mycoplasmal-bacterial, (6) concomitant mycoplasmal-viral, (7) chlamydial, (8) concomitant chlamydial-bacterial, (9) concomitant chlamydial-viral, and (10) unknown. Children aged 1 month to 13 years with radiographic and clinical evidence of pneumonia were enrolled. Between October 2001 and September 2002, we enrolled 165 patients. The etiologic agents were determined in 126 of the 157 (80.3%) patients who were finally diagnosed with pneumonia. Two blood cultures were positive for Haemophilus influenzae type b and Streptococcus pneumoniae. A viral infection alone was found in 28 of the 157 patients (17.8%), a bacterial (without mycoplasmal) alone infection in 42 (26.8%), a concomitant viral-bacterial infection in 28 (17.8%), and a mycoplasmal infection in 27 (17.2%) patients. RS virus was identified in 28 patients (17.8%), influenza A in 12 (7.6%), parainfluenza 3 in 8 (5.1%), adenovirus in 8 (5.1%), and influenza B and measles virus in 1 patient each. Streptococcus pneumoniae was the most common cause of bacterial pneumonia. We chose the initial treatment according to clinical and laboratory findings on admission (i.e., patients' age, clinical course, chest X-ray, and laboratory findings). In 68 of the 71 patients with bacterial (without mycoplasmal) pneumonia, an appropriate antibacterial-agent was prescribed. In 25 of the 27 patients with mycoplasmal pneumonia, clindamycin and minocycline were prescribed.