ObjectiveTo determine the efficacy of a single injection of platelet-rich plasma into the anterior vaginal wall at the mid-urethra compared to placebo, as there is emerging evidence that platelet-rich plasma may help treat female stress urinary incontinence. MethodsThis was a single-blind, randomized, placebo-controlled clinical trial at a single institution. Females with bothersome, demonstrable stress-predominant urinary incontinence were enrolled. Participants were randomized to either injection of 5 mL autologous platelet-rich plasma or saline at the anterior vaginal wall at the mid-urethra. The primary outcome was composite treatment success at six months, defined as a negative cough stress test and an answer of “much better” or “very much better” on the Patient’s Global Impression of Improvement. ResultsFifty patients were enrolled in the study and randomized to the platelet-rich plasma group (n = 25) or the saline placebo group (n = 25). There was no statistically significant difference in the primary outcome between the two groups. Adverse events were minor, and the rate of adverse events was similar between both groups. ConclusionsIn this randomized placebo-controlled study, we were unable to demonstrate a difference in stress urinary incontinence treatment success between platelet-rich plasma and saline injections. At this time, there is insufficient evidence to offer a one-time platelet-rich plasma injection into the anterior vaginal wall for treatment of female stress urinary incontinence.