Magnetic resonance pyelography (MRP) is a new noninvasive method which demonstrates dilated urinary tracts with no need of contrast agent injection. This study was aimed at technique optimization, using new fast sequences with high intrinsic contrast, to demonstrate the urinary tract in obstructive uropathy patients. Twelve consecutive patients and 4 healthy volunteers were included in this prospective study; all the exams were performed with a high gradient power 0.5-T unit using T2- weighted turbo SE sequences, acquired three-dimensionally on the coronal plane. Obstructive uropathy was caused in 9 patients by neoplastic lesions, in 2 by postoperative strictures and in 1 by inflammatory tissue. In all patients MRP depicted the dilated urinary tract optimally, with good morphological detailing and the accurate assessment of both level and cause of obstruction. In the healthy volunteers, the absence of dilatation did not permit the complete visualization of the urinary tract. To conclude, MRP is a new technique which permits high-quality imaging of the urinary tract. Further studies are needed to assess its actual potentials and clinical role.