The study was conducted to assess the role of M. pneumoniae, C. pneumoniae, and L. pneumophila in community - acquired pneumonia in children, 193 patients (age from 12 months to 15 years), admitted to the Respiratory Department of the National Hospital of Pediatrics, with symptoms of pneumonia from July 2010 to December 2010, were enrolled in the study. Multiplex PCR on nasopharyngeal aspirates were used to establish the diagnosis of acute M. pneumoniae, C. pneumoniae and L. pneumophylla infection. The results showed that atypical pneumonia was identified in 48/193 (24.8 percent). The median age was 3.7 (range 1-15) years. Mycoplasma pneumoniae PCR was positive in 42 (21.8 percent) cases, C. pneumoniaein 5 (2.6 percent) cases, L. pneumophylla in one (0.52 percent) case and co - infection. was present in 11 (22.9 percent). Two cases had co - infection with M. pneumoniae and C. pneumoniae. Severe atypical pneumonia was occurred in 43.7 percent. In conclusion, M. pneumoniae, C. pneumoniae, L. pneumonia were identified in 24.8 percent of children with CAP in this series and mixed infections were common (22.9 percent) and severe atypical pneumonia was occurred in 43.1 percent. Multiplex PCR assay could provide earlier diagnosis of M. pneumoniae, L. pneumophylla , C. pneumoniae infection.