We examined 73 children with respiratory infections for Chlamydophila (Chlamydia) pneumoniae and Mycoplasma pneumoniae using real-time PCR assay and serological tests. C pneumoniae and M. pneumoniae infections were found in 11 (15.1%) and 6 (8.2%) cases, respectively. The sensitivities and specificities of real-time PCR versus definite diagnosis of acute infection were 63.6% and 100% for C. pneumoniae, and 100% and 100% for M. pneumoniae, respectively. C pneumoniae PCR-negative results appeared to be due to poor growth of the organism. The sensitivity and specificity of ImmunoCard tests were 33.3% and 82.1%, respectively, indicating that the efficacy of rapid diagnosis was disputable. The present results suggest that real-time PCR is suitable for rapid diagnosis as a first screening test to determine first-line antibacterial agents to be used against these infectious diseases.