The purpose of this research is to develop a diagnostic reference level for computed tomography (CT) suitable for Korean medical purposes. The direction of CT application and details on patient dose were investigated by survey, and the dose measurement is targeted in general hospitals registered with the Korean Hospital Association. The dose measurement was done with head and body phantom, and an accurate dosimeter was utilised in medical institutions that participated in the survey. The survey and dose measurements on the patient dose showed that the 75th percentiles in the distribution of weighted CT dose index (CTDIw) were 50.5 and 45.4 mGy for the head and 14.4 and 25.30 mGy for the body portions, respectively. Based on these research data, the target patient doses that are believed to be achievable for CT examination in Korean circumstances are about 48 +/- 4 mGy in the head and 20 +/- 8 mGy in the body.