To evaluate the use of papaverine-induced erection as a diagnostic test in men with erectile dysfunction, 24 patients had papaverine injected into the corpus cavernosum. The results of the papaverine test in combination with the tentative diagnosis, based upon patient history, clinical examination and peno-brachial pressure index, gave in most cases sufficient information about the function of the penile vessels to decide in which patients a selective arteriography or a cavernosography was indicated. Two patients developed priapism after the papaverine injection.