Aim of this work is to compare the radiation dose of two direct digital systems in the radiographic chest study in order to verify the overall exposure levels in patients of different sizes. Digital system FUJIFILM DR velocity Ufp and a KODAK DIRECT VIEW DR 7500 (with automatic exposure) were tested on a total of 300 patients randomly assigned to one of two groups of 150 subjects. The patients were further subdivided according to Body Mass Index (BMI) in three subgroups (underweight, normal weight, overweight). The Entrance Surface Dose (ESD) values for the posteroanterior (PA) and lateral (LL) projections of chest examinations were calculated based on the exposure parameters used in diagnostic practice. Mean dose delivered was smaller with Kodak system than Fuji system for all groups of patients in the PA view (40% for underweight, 32% normal type and 10% overweight); in the LL view mean dose delivered was smaller with Fuji system than Kodak for overweight patients with a difference of 52 %. From the preliminary results shown in this work, we concluded that digital systems for chest imaging can easily give an high dose if not used properly (no standard technique), especially in the presence of auto exposure systems with over standard patients.