Two patients with severe bladder disease have undergone temporary urinary diversion with a sigmoid conduit as part of planned reconstruction of the lower urinary tract. Their lower urinary tracts have been reconstituted successfully by means of sigmoid cystoplasties. Experimental data further support use of the sigmoid conduit vis-a-vis use of the traditional ileal conduit for long-term diversion and reconstruction. A main advantage of the sigmoid segment is the ability to create an antirefluxing ureterointestinal anastomosis. We have demonstrated that ureteral reflux from ileal conduits produces histologic evidence of pyelonephritis. Colonic conduits, by preventing reflux, reduce the frequency of pyelonephritis and function in an equivalent manner to ileal segments when used either for cutaneous diversion or ureteral substitution in reconstruction.