RESULTSThere were 301 operations; the difference in bladder perforations was not statistically significant, at one/147 TVT (0.7%), and three/ 154 SPARC (1.9%), with the difference in rate of 0.013 (95% confidence interval (CI) − 0.01 to 0.04; odds ratio 2.89, 95% CI 0.30-28.21; P = 0.62), and nor were differences in estimated blood loss of > 100 mL (TVT, 32/147,21 (TVT 7/147, 4.8%; SPARC 16/152, 10.5%). Acute urinary retention (TVT none of 147; SPARC 10/154, 6.5%; odds ratio ∞ , 95% CI 2.2-∞ ; P = 0.002) and subjective cure (TVT 128/147, 87.1%; SPARC 117/153, 76.5%; odds ratio 2.07, 95% CI 1.13-3.81; P = 0.03) were statistically significantly different. CONCLUSIONThese results are consistent with clinical equivalence between TVT and SPARC for bladder perforation. There was no statistically significant difference between TVT and SPARC in blood loss, urgency or objective cure of SUI symptoms at 6 weeks. However, SPARC was more difficult to adjust correctly, and a statistically significant number of patients required loosening of the tape in theatre ( P = 0.002). TVT had a lower rate of vaginal erosion and a statistically significantly higher cure rate of subjective SUI symptoms than SPARC. Overall, voiding difficulty (loosening of the tape), urgency and vaginal mesh erosion were the most important clinical problems. This trial showed the importance of testing new devices which appear to be similar, but which might have relevant differences. There was no financial assistance for this study, and a long-term follow up is planned. KEYWORDSrandomized controlled trial, TVT, SPARC, stress incontinence, complications, erosion OBJECTIVETo establish the equivalence between the tension-free vaginal tape (TVT) and the suprapubic urethral support sling (SPARC). Approximately 35% of women have stress urinary incontinence (SUI), and although TVT is now perceived as the standard treatment, the SPARC is a very similar procedure and is thought to have fewer peri-operative complications. PATIENTS AND METHODSPatients with clinical SUI were recruited from public and private urology/urogynaecology clinics, and participated in the trial of TVT vs SPARC. The primary outcome was bladder perforation; secondary outcomes were blood loss, voiding difficulty, urgency, and cure of SUI symptoms. Sample size calculations, based on an estimated 2% perforation rate, showed that 290 patients would be needed to detect a clinically significant difference of 5%. Stratification was by previous incontinence surgery and the experience of the surgeon.