In pediatric radiology, radiological protection isof vital importance due to the great radio-sensitivity of body tissuesin childhood, which can come to present stochastic effects as childrenhave a longer life expectancy. The objective of this research isto establish diagnostic reference levels in chest exam pediatricpatients. The study, carried out in one of the largest pediatriccenters of the city of Medellin, the capital of the Department ofAntioquia, consisted of the calculation of the Entrance Skin Dose(ESD) for a sample of 814 chest radiographic studies in the anteroposterior(AP) and left lateral (L LAT) projections, and it was compared withthe doses obtained with the computational program PCXMC 2.0. Forthe estimate of the Entrance Skin Dose, data were collected from theexams, including the size of the radiation field, mAs and kVp. TheESD in chest exams for 5-year-old children was the only one thatexceeded the international reference levels, giving evidence ofthe need to optimize the techniques used in this type of study inthe institution under evaluation.