OBJECTIVE Interventional radiological procedures have important legal implications. The importance of informing the patient ("informed consent") before such procedures is examined in the light of German legal cases. METHODS The German legal literature is reviewed and recent judgments of the Courts are cited. RESULTS No all-embracing rules can be obtained from the judgments of the German Courts. Mostly one is dealing with individual judgments which can help in a general sense. The patient should be informed well before elective invasive procedures ("informed consent") and the amount of detailed information which is requested to be given to the patient appears to be increasing. Reversal of this trend in the future is unlikely. CONCLUSIONS These judgments are of immediate significance for any radiologist who carries out interventional radiological procedures. In the case of complicated techniques the patient should be informed at the time of admission and a definite date for the procedure should be set. Explanations given on the evening before the procedure are deemed to be too late, unless there are exceptional circumstances. Where new forms of therapy are attempted, the information should be even more detailed. In particular it is necessary to stress the experimental nature of the procedure.