Abstract Purpose Urethral fistula and dehiscence are common after hypospadias surgery. Preoperative androgens have been considered to reduce these complications although this consideration is not evidence-based. Dermatologists have reported the benefits of topical estrogens on skin healing. We investigated whether the preoperative use of topical promestriene could reduce healing complications in hypospadias surgery. Our primary objective was to demonstrate a reduction of healing complications with promestriene vs placebo. Impact on reoperations and other complications, clinical tolerance, bone growth, and biological systemic effects of the treatment were also considered. Methods We conducted a prospective, randomized, placebo-controlled, double-blind, parallel group trial between 2011 and 2015 in 4 French centers. One-stage transverse preputial island flap urethroplasty (onlay urethroplasty) was selected for severe hypospadias. Promestriene or placebo was applied on the penis for 2 months prior to surgery. The primary outcome was the presence of postoperative urethral fistula or dehiscence in the first year postsurgery. For safety reasons, hormonal and anatomical screenings were performed. Results Out of 241 patients who received surgery, 122 patients were randomized to receive placebo, and 119 patients received promestriene. The primary outcome was unavailable for 11 patients. Healing complications were assessed at 16.4% (19/116) in the placebo vs 14.9% (17/114) in the promestriene arm, and the odds ratio adjusted on center was 0.93 (95% confidence interval 0.45-1.94), P = 0.86. Conclusions and relevance Although we observed an overall lower risk of complications compared to previous publications, postsurgery complications were not different between promestriene and placebo, because of a lack of power of the study or the inefficacy of promestriene.