Introduction and hypothesis: Synthetic midurethral slings (MUSs) have shown similar cure rates in several short- and medium-term follow-up studies. Recently, long-term follow-up studies have indicated that the cure rate is higher following the retropubic midurethral sling (RPMUS) compared with the transobturator midurethral sling (TOMUS) procedure. The aim was to evaluate the efficacy of synthetic MUSs and to examine the influence of department and surgeon volume and patient-related factors on the cure rate of synthetic MUSs. Methods: A retrospective cohort study based on a national population over a 5-year period (2007–2011) using data from the Danish Urogynaecological Database (DugaBase). Results: A total of 4519 women with first-time MUS were registered in the DugaBase. Cure was achieved in 1242/1639 (75.78%) at a 3-month follow-up. RPMUSs were more frequently in use in high-volume departments compared with the other departments and more often implanted by high- than low-volume surgeons. Women treated by a medium- (adjusted OR 1.82; 95% CI 1.01–3.28, “frequency”) or high-volume surgeon (1.98; 1.18–3.32, “frequency”) had an increased probability of cure compared with women treated by a low-volume surgeon. The difference was only significant for women who received a TOMUS. Conclusions: This national population-based cohort study confirmed a high cure rate of synthetic MUSs at short-term follow-up. It is the largest study to indicate a learning curve for TOMUS. Patients were not actively involved in which synthetic MUS was to be performed as the choice of surgical option was made at the departmental level.