OBJECTIVES: The objective was to analyse the cost-effectiveness of solifenacin succinate flexible dosing for the relief of overactive bladder symptoms (OAB) such as urinary frequency and urgency with or without incontinence in Norway, Finland, Sweden and Denmark. METHODS: A decision analytic model was used to simulate the results for a group of patients with OAB. The model was built with a 1 year time horizon and compared the cost and effectiveness of solifenacin flexible dosing (5 mg and 10 mg) vs. tolterodine 4 mg SR and placebo. The analysis was based on two large randomised controlled trials. Resource-use was based on clinical guidelines in the Nordic countries as well as published literature. Pad use was collected prospectively in the trials. Unit costs were obtained from official sources in each of the Nordic countries. Medication, treatment costs and indirect costs were included in the analysis. Effectiveness was measured as a reduction in OAB symptoms (urge incontinence episodes, incontinence episodes, urgency episodes and micturitions) and quality-adjusted life years (QALYs). RESULTS: For almost all effectiveness parameters, solifenacin flexible dosing was significantly more effective compared to tolterodine 4 mg SR and placebo. Moreover, solifenacin flexible dosing was less costly compared to tolterodine 4 mg in all Nordic countries (dominant strategy). Compared to placebo, solifenacin was also considered a cost-effective treatment strategy, e.g. with a cost per QALY gained of €27.000 in Sweden. An analysis using solifenacin split data for patients taking 5 mg and 10 mg compared to tolterodine 4 mg SR also showed, that solifenacin was a cost-effective treatment strategy. CONCLUSION: Solifenacin flexible dosing is a cost-effective treatment strategy for patients with OAB in the Nordic countries. A sensitivity analysis using solifenacin split data supported this conclusion, which revealed that the results were robust.