The method and utilization of fluoroscopically-controlled television-monitored aspiration of renal masses following the production of a urogram is described and discussed. Fifteen patients examined by this method are reported and the results evaluated. The desirability of performing this examination in most renal masses with the exception of suspected renal abscesses is stressed. It is recommended that the aspiration immediately follow the urography and precede the angiography or nephrotomography in the order of investigation of renal masses.