ntroduction and hypothesis: Our purpose was to compare the prevalence of urinary incontinence (UI) 3 and 12 months after vaginal vs cesarean delivery of twins after 34 weeks of gestation. Methods: This was a multicenter prospective cohort study conducted at 172 French maternity units and included 2812 primiparous women with twins with no prior history of UI. Participants were enrolled at the time of delivery and followed up to 12 months postpartum. The primary outcome was the prevalence of UI, both stress and urge, 3 months postpartum, based on the patient reporting any frequency of urine leakage to the first question of the International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF). The Pelvic Floor Distress Inventory - Short Form 20 (PFDI-20), Pelvic Floor Impact Questionnaire - Short Form 7 (PFIQ-7), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12), and Medical Outcome Study Short Form-12 (SF-12) were also used. Results: The ICIQ-SF was completed by 1155 (39.8%) and 800 (27.5%) women, respectively, at 3 and 12 months postpartum; 556 (48%) had delivered vaginally and 599 (52%) by cesarean section. The prevalence of UI at 3 months was 26% overall and was significantly higher in the vaginal delivery group at both 3 months (35% vs 17% in the cesarean group, p < 0.0001) and 12 months postpartum (38% vs 24%, p < 0.0001). UI was predominantly stress or mixed. The risk factors for UI at 3 months, determined by multivariate modeling, were vaginal delivery [odds ratio (OR) 3.073, 95% confidence interval (CI) 2.3-4.105, p < 0.0001) and body mass index >25 in early pregnancy (OR 1.620, 95% CI 1.188-2.209, p = 0.0023). Conclusions: Vaginal delivery is a risk factor for UI at 3 months after twin birth.