We carried out a nationwide questionnaire survey of pediatric computed tomography (CT) in 339 facilities. Most facilities operated multi detector-row CT (MDCT), and over half operated 64, 128, 256 and 320-slice MDCT. In 32% of facilities, pediatric CT protocols were set taking image quality and dose into consideration. However, in the other facilities, pediatric CT protocols may not be optimized because there is no clear standard for image quality or dosage for pediatric CT examinations in Japan. To promote the optimization of pediatric CT protocols, we regard it as an urgent task to establish diagnostic reference levels for pediatric CT examinations.