b＞Objectives: /b＞There are no reports on the radiation doses of neonates admitted to Neonatal Intensive Care Units (NICUs) in Korea. Therefore, this study evaluated the radiation dose of diagnostic x-rays performed in NICUs using mobile x-ray machines. b＞Methods:/b＞ We retrospectively analyzed the number and doses of radiographs of 231 very low-birth-weight infants (VLBWI) (birth weight 1,500g) who were admitted to Soonchunhyang University Bucheon Hospital from 2011 to 2016. We exclude the number of patients 1) who discharged by transfer to other hospital (n= 23), 2) death (n=35) during the hospitalization period, and 3) who have been admitted for more than 1 year (n=1) from total number of patients. We compared the number and doses of radiation according to clinical characteristics and morbidities. The entrance surface doses (ESD) were calculated using the non-dosimeter dosimetry formula to measure radiation doses. b＞Results:/b＞ All infants required at least one radiograph. The subjects required median of 26 radiographs per infant and about 25% of the neonates had more than 50 radiographs. The number of taken radiographs were higher in infants who had lower birth weight, respiratory distress syndrome, bronchopulmonary dysplasia, longer duration of central venous catheter, and longer hospital stay (all p0.001). The ESD varied between 0.18 and 14.57mGy and the ESD per radiograph ranged from 0.049 to 0.069mGy. b＞Conclusion: /b＞VLBWIs treated in our NICU had high radiation and gonad exposures compared with previous studies. Additional studies should be followed to minimize the cumulative exposure dose and to achieve optimal image quality.