BACKGROUND: Despite the wide use of azathioprine/mercaptopurine (AZA/MP) therapy in the management of both Crohn's disease (CD) and ulcerative colitis (UC), approximately 20% of patients cannot tolerate the drugs and 30% do not respond. AIM: To examine the efficacy and safety profile of methotrexate (MTX) in patients with CD or UC who are either intolerant or non-responsive to AZA/MP. METHODS: A total of 131 patients with IBD treated with MTX were identified. Retrospective data were obtained by case note review. Clinical response (defined as steroid withdrawal, normalization of previously raised CRP or physician's clinical assessment of improvement) was assessed at 6 months. RESULTS: Clinical response in Crohn's disease occurred in 18 of 29 patients (62%) refractory to AZA/MP and 42 of 70 patients (60%) intolerant to AZA/MP, with no difference between the groups (P = 1.0). In UC, clinical response was seen in 7 of 9 (78%) patients refractory to AZA/MP and 15 of 23 (65%) intolerant to thiopurines. MTX was well tolerated in a majority of individuals. CONCLUSIONS: Methotrexate appears effective in both CD and UC patients who fail to respond to or are intolerant to AZA/MP therapy.