Dynamic renal scintigraphy is a successful and minimally invasive technique for evaluating renal function. An extension to the basic technique involving fast-frame acquisition and a modified analysis is described which enables ureteric function to be examined. Ureteric peristalsis was assessed in 32 patients using this technique. The results from 5 representative studies are described in detail. Normally functioning ureters exhibit peristaltic contractions at a frequency of up to 3/min. Hyperperistalsis that exceeds 4 contractions/min is associated with obstruction. Peristaltic behaviour in 9 patients examined before and after ESWL was not altered.