Human cytomegalovirus (CMV) is the most common cause of congenital and perinatal infections throughout the world. Chlamydia trachomatis during pregnancy also cause a wide variety of perinatal complications and neonatal pneumonia. We report a case of neonatal pneumonia caused by intrauterine dual infection with CMV and C. trachomatis. A two-day-old term infant was presented with tachypnea. His chest roentgenogram showed the interstitial pneumonia-like interstitial infiltrates. Results of microbiological examinations showed that he had been simultaneously infected with CMV and C. trachomatis in uterus.