The purpose of our retrospective 3-year study was to analyse and compare clinical and epidemiological characteristics in hospitalized patients older than 6 years with community-acquired pneumonia (CAP) caused by Chlamydia pneumoniae (87 patients) and Mycoplasma pneumoniae (147 patients). C. pneumoniae and M. pneumoniae infection was confirmed by serology. C. pneumoniae patients were older (42·12 vs. 24·64 years), and were less likely to have a cough, rhinitis, and hoarseness (P<0·001). C. pneumoniae patients had higher levels of C-reactive protein (CRP), and aspartate aminotransferase (AST) than M. pneumoniae patients (P<0·001). Pleural effusion was recorded more frequently in patients with M. pneumoniae (8·84 vs. 3·37%). There were no characteristic epidemiological and clinical findings that would distinguish CAP caused by M. pneumoniae from C. pneumoniae. However, some factors are indicative for C. pneumoniae such as older age, lack of cough, rhinitis, hoarseness, and higher value of CRP, and AST.