© 2016 American Medical Association. All rights reserved. IMPORTANCE Women with refractory urgency urinary incontinence are treated with sacral neuromodulation and onabotulinumtoxinA with limited comparative information. OBJECTIVE To assess whether onabotulinumtoxinA is superior to sacral neuromodulation in controlling refractory episodes of urgency urinary incontinence. DESIGN, SETTING, AND PARTICIPANTS Multicenter open-label randomized trial (February 2012-January 2015) at 9 US medical centers involving 381 women with refractory urgency urinary incontinence. INTERVENTIONS Cystoscopic intradetrusor injection of 200 U of onabotulinumtoxinA (n = 192) or sacral neuromodulation (n = 189). MAIN OUTCOMES AND MEASURES Primary outcome, change from baseline mean number of daily urgency urinary incontinence episodes over 6 months, was measured with monthly 3-day diaries. Secondary outcomes included change from baseline in urinary symptom scores in the Overactive Bladder Questionnaire Short Form (SF); range, 0-100, higher scores indicating worse symptoms; Overactive Bladder Satisfaction questionnaire; range, 0-100; includes 5 subscales, higher scores indicating better satisfaction; and adverse events. RESULTS Of the 364 women (mean [SD] age, 63.0 [11.6] years) in the intention-to-treat population, 190 women in the onabotulinumtoxinA group had a greater reduction in 6-month mean number of episodes of urgency incontinence per day than did the 174 in the sacral neuromodulation group (-3.9 vs -3.3 episodes per day; mean difference, 0.63; 95%CI, 0.13 to 1.14; P = .01). Participants treated with onabotulinumtoxinA showed greater improvement in the Overactive Bladder Questionnaire SF for symptom bother (-46.7 vs -38.6; mean difference, 8.1; 95%CI, 3.0 to 13.3; P = .002); treatment satisfaction (67.7 vs 59.8; mean difference, 7.8; 95%CI, 1.6 to 14.1; P = .01) and treatment endorsement (78.1 vs 67.6; mean difference; 10.4, 95%CI, 4.3 to 16.5; P .001) than treatment with sacral neuromodulation. There were no differences in convenience (67.6 vs 70.2; mean difference, -2.5; 95%CI, -8.1 to 3.0; P = .36), adverse effects (88.4 vs 85.1; mean difference, 3.3; 95%CI, -1.9 to 8.5; P = .22), and treatment preference (92.% vs 89%; risk difference, -3%; 95%CI, -16%to 10%; P = .49). Urinary tract infections were more frequent in the onabotulinumtoxinA group (35%vs 11%; risk difference, -23%; 95%CI, -33%to -13%; P .001). The need for self-catheterization was 8%and 2%at 1 and 6 months in the onabotulinumtoxinA group. Neuromodulation device revisions and removals occurred in 3%. CONCLUSIONS AND RELEVANCE Amongwomen with refractory urgency urinary incontinence, treatment with onabotulinumtoxinA compared with sacral neuromodulation resulted in a small daily improvement in episodes that although statistically significant is of uncertain clinical importance. In addition, it resulted in a higher risk of urinary tract infections and need for transient self-catheterizations.