OBJECTIVES: To examine the cost-effectiveness of continued treatment for patients with moderate-severe Crohn's disease in clinical remission, with a combination of anti-tumour necrosis factor alpha [anti-TNFα] [infliximab] and immunomodulator therapy compared with two different withdrawal strategies:  withdrawal of the anti-TNFα therapy; and  withdrawal of the immunomodulator therapy, respectively. METHODS: A decision-tree model was constructed mimicking three treatment arms:  continued combination therapy with infliximab and immunomodulator;  withdrawal of infliximab; or  withdrawal of the immunomodulator. Relapses in each arm are managed with treatment intensification and re-institution of the de-escalated drug according to a prespecified algorithm. State-dependent relapse risks, remission probabilities, and quality of life weights were collected from previous published studies. RESULTS: Combination therapy was less costly and more efficient than the withdrawal of the immunomodulator, and more costly and more efficient than withdrawal of infliximab. Whether or not combination therapy is cost-effective, compared with the alternatives, depends primarily on current pharmaceutical prices and the willingness-to-pay per additional quality-adjusted life-year [QALY]. CONCLUSIONS: Combination therapy using a combination of anti-TNFα [infliximab] and an immunomodulator is cost-effective in the treatment of Crohn's disease compared with treatment cycles in which the immunomodulator is withdrawn. Combination treatment is cost-effective compared with treatment cycles in which infliximab is withdrawn, at prices of infliximab below€192/100 mg, given a willingness-to-pay threshold at€49 020 [Sweden] per additional QALY.