OBJECTIVES: Combination therapy with an α-blocker and an antimuscarinic is recommended for men with moderate-to-severe LUTS/BPH if symptom relief is insufficient with monotherapy. We evaluated the cost and resource utilisation, in the UK healthcare system, of three treatment scenarios: tamsulosin (0.4mg) monotherapy; tolterodine (modified release, 4mg) + tamsulosin given concomitantly; and fixed-dose combination (FDC) of solifenacin 6mg + oral controlled absorption system [OCAS™] formulation of tamsulosin (TOCAS, 0.4mg).  METHODS: A Markov model, with a monthly cycle length and 1-year time horizon, compared the cost of treating 1,000 men with LUTS/BPH who have moderate-to-severe storage symptoms and voiding symptoms. All patients were initially treated with tamsulosin monotherapy. Patients with inadequately controlled symptoms at week 12, based on Total Urgency and Frequency Score (TUFS, the daily sum of all recorded Patient Perception of Intensity of Urgency Scale [PPIUS] scores from micturition diaries), were considered for FDC solifenacin 6mg + TOCAS or tolterodine + tamsulosin. Patients adequately controlled at week 12 continued tamsulosin monotherapy. Thereafter, patients could discontinue therapy each month based on reported medication persistence data. Patients who discontinued treatment were eligible for surgery or other medical management.  RESULTS: Compared with tamsulosin monotherapy, total costs per patient, over a 1-year time horizon, were reduced by £133.75 for tolterodine + tamsulosin and reduced by £154.85 for FDC solifenacin 6mg + TOCAS. CONCLUSIONS: Our findings suggest FDC solifenacin 6mg + TOCAS reduces annual healthcare costs compared with tamsulosin monotherapy and tolterodine + tamsulosin in patients with inadequately controlled storage symptoms. Lower total cost for FDC solifenacin 6mg + TOCAS and tolterodine + tamsulosin versus tamsulosin monotherapy was largely driven by improved symptom control. The relatively lower total cost for FDC solifenacin 6mg + TOCAS versus tolterodine + tamsulosin (£21 per patient/year) was principally due to improved persistence with FDC solifenacin 6mg + TOCAS.