Purpose:An ill-defined proportion of patients undergoing urethroplasty fail to experience improvement in lower urinary tract symptoms (LUTS) despite being stricture-free. We aim to identify the incidence, associations and causes of “LUTS failure” after urethroplasty.Materials and Methods:Patients undergoing urethroplasty over a 6-year period were offered enrollment in a prospective study examining urinary function after urethroplasty. Patients were assessed preoperatively and 6 months postoperatively using the International Prostate Symptom Score (IPSS) and cystoscopy. “LUTS failure” was defined as ≤3-point improvement in IPSS despite an anatomically successful urethroplasty. Multivariable logistic regression was utilized to evaluate the association between patient factors and “LUTS failure.”Results:Of 365 patients meeting inclusion criteria, mean postoperative IPSS (20.3 vs. 5.4, p <0.0001) and median urinary quality of life (UQOL; 5 vs. 1; p <0.0001) were significantly improved. Despite being stricture-free, 7.7% of patients reported “LUTS failure” and 10.1% reported UQOL nonresponse. On multivariable logistic regression, increasing age (OR 1.04, 95% CI 1.01–1.06; p=0.006) and hypospadias (OR 18.2, 95% CI 2.1–156.0; p=0.008) were associated with “LUTS failure,” while stricture location (p=0.76), length (p=0.14), previous urethroplasty (p=0.96), failed endoscopic treatment (p=0.17), type of urethroplasty (p=0.93) and other etiologies were not. Qualitatively, the most likely causes of “LUTS failure” were detrusor underactivity (39.3%), overactivity (21.4%), pelvic floor dysfunction (21.4%) or benign prostatic hyperplasia (14.3%). Only increasing age was associated with UQOL nonresponse (OR 1.03, 95% CI 1.01–1.07; p=0.02).Conclusions:While many patients experience improved voiding function after urethroplasty, 7.7% experience “LUTS failure” and 10.1% report UQOL nonresponse. Both occurrences are independently associated with increasing patient age and most commonly related to detrusor underactivity.