PURPOSE: Few studies have characterized longer-term outcomes after retropubic and transobturator mid urethral slings. MATERIALS AND METHODS: Women completing 2-year participation in a randomized equivalence trial who had not undergone surgical re-treatment for stress urinary incontinence were invited to participate in a 5-year observational cohort. The primary outcome, treatment success, was defined as no re-treatment or self-reported stress incontinence symptoms. Secondary outcomes included urinary symptoms and quality of life, satisfaction, sexual function and adverse events. RESULTS: Of 597 women 404 (68%) from the original trial enrolled in the study. Five years after surgical treatment success was 7.9% greater in women assigned to the retropubic sling compared to the transobturator sling (51.3% vs 43.4%, 95% CI -1.4, 17.2), not meeting prespecified criteria for equivalence. Satisfaction decreased during 5 years but remained high and similar between arms (retropubic sling 79% vs transobturator sling 85%, p=0.15). Urinary symptoms and quality of life worsened with time (p <0.001), and women with a retropubic sling reported greater urinary urgency (p=0.001), more negative impact on quality of life (p=0.02) and worse sexual function (p=0.001). There was no difference in the proportion of women experiencing at least 1 adverse event (p=0.17). Seven new mesh erosions were noted (retropubic sling 3, transobturator sling 4). CONCLUSIONS: Treatment success decreased during 5 years for retropubic and transobturator slings, and did not meet the prespecified criteria for equivalence with retropubic demonstrating a slight benefit. However, satisfaction remained high in both arms. Women undergoing a transobturator sling procedure reported more sustained improvement in urinary symptoms and sexual function. New mesh erosions occurred in both arms over time, although at a similarly low rate.