The Snodgrass technique and its modifications have become a preferred method for all varieties of hypospadias in the past decade. However, fistula is the most common complication of this technique. The aim of this study was to investigate the importance of the single and double flap to prevent fistula formation in the Snodgrass procedure. Tubularized incised plate urethroplasty, using a single or the double flap, was undertaken in 74 consecutive boys (median age 6.6 years old, range 1-15) within the last 4 years. In the first 29 patients (group 1), a dorsolateral flap was rotated laterally for covering the neourethra and in the remaining 45 patients (group 2) the neourethra was covered with dorsal double dartos flaps. In group 1, fistula in 4 patients and partial glanular dehiscence in 1 patient were detected. There was no fistula formation in group 2. For preventing fistula formation, urethral covering by a well-vascularized dorsal double-layer dartos flap should be the basic part of the Snodgrass procedure. Copyright 2007 S. Karger AG, Basel.