The role of radiology within the wide variety of disciplines involved in patient care, and the relative values of the increasing number of investigative techniques available for patient care were discussed with particular reference to diseases of the urinary tract. The concept of the definitive diagnostic test was presented and the ways in which the level of confidence in a particular diagnosis may be increased were illustrated with examples of simple renal cyst and renal cell carcinoma. The management role of radiology was also reviewed, with emphasis on the determination of the precise stage of the disease and the developing application of interventional radiology to therapy.