Radiological units present different exposure values, (even by a factor 100), for the same radiological examination unless special programs are performed in order to optimize the examinations and to reduce variations. The program named DQM, mentioned in the Circular n. 62 of the Ministry of Health, is planned for mammographic optimization. The steps of the programme are: a) collection of the working parameters in each unit, b) dose and image quality evaluation, c) communication of the results and suggestion for corrective actions. The practical aspects of the program and the results of measurements in 65 mammographic units are presented and discussed. The importance of the Quality Assurance, performed by radiologists and physicists is underlined.