The Medical Physics Group at the Complutense University of Madrid has been co-ordinating, for approximately 1 year, a project on optimization of radiation protection in diagnostic radiology, in co-operation with the other states of the European Community. Exhaustive data on the subject, which offer accurate results on patient dosimetry for the different types of examination, are the final aim of the project. So far, it has been possible to analyse in detail the data from the National Institute of Health (NIH), which manages the care of about 96% of the Spanish population, plus the findings from several hospitals, outpatient centres and private clinics of the community of Madrid, which allowed us to perform the first dose estimation and to extrapolate them to the rest of Spain. The following estimation are presented: annual frequency of different examinations, their variation from 1985 to 1986, number of diagnostic rooms used for a given minimum of annual examinations, organ doses for different examinations, effective dose-equivalent, genetically significant dose for some examinations, as well as the collective dose.