Between 1967 and 1986 185 children (246 renoureteral units) and 21 adults (25 renoureteral units) with megaureters have been treated surgically in our department. 85 of the children had primary obstructive megaureters, 77 children showed secondary megaureters, whereas 23 others showed either a gross ureteral dilatation due to an ureterocele or gross reflux. All of the adult patients presented with primary obstructive megaureters. 122 children (65.9%) and 15 adults (71.4%) underwent ureterocystoneostomy (UCN) using various techniques, the Psoas Hitch technique being exclusively the method of choice since 1977 with markedly better results. The indication for ureteral tapering was considered extremely conservatively. In the rest of the patients the elimination of the infravesical obstruction alone was sufficient or a nephrectomy/nephroureterectomy had to be performed due to a non-functioning kidney. The percentage of UCN in primary obstructive megaureters throughout the years (79% in 1967-1971 and 63% in 1977-1986) and its significant decrease in secondary megaureters from 71% to 39% during the same time period displays the conceptional changes in the therapy regimen. The majority of children and adults with primary obstructive megaureters can be treated conservatively. UCN should be indicated for cases with synchronous reflux and/or recurrent febrile urinary tract infections. The indication for ureteral tapering should be considered very carefully. Especially in secondary megaureters the indication for ureteral tapering and reimplantation is rare since the adequate relief of the infravesical obstruction may be sufficient alone in many of the cases.