The authors report the results of the staging of urinary bladder cancers by means of MRI using a new ferrous contrastographic solution called JKA1. Eighteen patients with proved bladder neoplasms were examined by means of MRI: the bladder was filled with physiological solution first, and then with JKA1. Six patients were studied also after filling their bladders with Gd-DTPA solution (1:50). The results show that the use of JKA1, a T2-positive contrast medium, improved MR capabilities in the evaluation of small lesions (phi less than 1 cm) with minimal invasion of bladder wall; MR staging accuracy was 66.6% with the physiological solution and 77.8% with JKA1. The authors confirm the need for a wider MR study, in particular of T2 lesions (a critical subject for staging and surgical management) to assess MR diagnostic capabilities.