OBJECTIVE The aim of the study is to determine the incidence of adverse reactions to iodinated contrast media and to characterise them in a group of outpatients, inpatients and emergency patients in a private hospital in Barcelona. METHODS A retrospective cohort study was carried out over a 60 months period, from February 2002 to February 2007, analysing the patients who underwent to iodinated contrast radiological examinations. Adverse reactions were evaluated from the manual record format developed following the requirements of the Quality Assurance Program in Radiology. Study variables were, administration route, contrast media dose, adverse reaction type, and signs and symptoms. Statistical analysis was descriptive. RESULTS A total of 68 (0.3 %) of adverse reaction were registered of which 64 were mild (94.1%), 4 moderate (5.9%) and none severe. On the basis of the administration route (intravenous or oral) adverse reaction were 67 (94%) and 1 (6%) respectively. With a 40-80ml contrast media dose by injection, mild adverse reactions were 87.5%, moderate 12.5% and severe 0%. With a 90-150ml contrast media dose by injection, mild adverse reaction were 94.9% and moderate 5.1%. CONCLUSIONS The number of adverse reaction using iodinated contrast media is low and are they are generally mild; however the nurse must be ready to recognise and treat them.