Crohn's disease and ulcerative colitis frequently recur after effective induction therapy. Accordingly, improved maintenance therapy remains the greatest unmet medical need in treating these disorders. Although 5-aminosalicylate compounds are widely used to maintain remission in Crohn's disease, the scientific evidence supporting this practice is poor. Antimetabolites (azathioprine, 6-mercaptopurine, and methotrexate) and infliximab are moderately effective in high-risk patients; however, these drugs might cause significant adverse effects. For patients with ulcerative colitis, maintenance therapy with 5-aminosalicylate compounds is a mainstay of treatment, being both effective and safe. However, this approach is not effective in a minority of patients. Although the purine metabolites can be used to treat these patients, strong scientific evidence that supports this practice is lacking. An initial experience with probiotic bacteria for maintenance of remission in ulcerative colitis seems promising. This article reviews the data from randomized, controlled trials of maintenance therapy in inflammatory bowel disease.