Introduction Prior information in the realization of an invasive intervention is crucial. Indeed, the patient has to know theoretically his disease, diagnostic and therapeutic means, but also the risks of the used technique. The habits of information vary many from one center to another, in spite of the proposition of an information leaflet written by the French Society of Cardiology. Our aim was to evaluate the efficacy of the written information on patients hospitalized for coronary arteriography. Methods Among patients hospitalized for realization of a programmed coronarography, a questionnaire was delivered before the information leaflet. The knowledge of the patients was so tested (27 items) before and after the reading of the information sheet (not limited time). The knowledge of the patients concerning coronarography indication, modalities, benefits, possible complications or still later possibilities was informed. Results Thirty-four patients were included: all knew hospitalization reason, 86% were men, middle-aged 65 (IC 95% 60–70). Thirty-four percent (15–54) had studied in higher education. Ninety-seven percent had had information before. Only 56% (38–74) were informed about the mode of anesthesia, 36% (19–53) duration, 69% (53–86) the injection of iodine, 44% the risk of allergy, 53% the risk of bruise, 15% of the cardiac risks, 21% the renal risks. Seventy-one percent knew the diagnostic benefits, 44% the possible coronary angioplasty, 17% the eventuality of a bypass surgery. The delivery of the information leaflet did not modify the knowledge on most of these items, in particular the modalities and the profits. The risks were known significantly better for the allergy ( P = 0.019), the bruise ( P = 0.018), the cardiac risks (0.001). Conclusions The population benefiting from a coronarography considers to be enough informed. However, knowledge of the modalities, profits and risks is very low. The delivery of the consensual leaflet does not allow improving the situation, except as far as concerned the complications. Better information is so indispensable, not only to obtain a better support of the patient in the treatment, but also to prevent the forensic implications. The improvement of the information must be multifactorial, but usually used means could be not sufficient.