Since 1964 only nine cases of multiple myeloma occurring in the setting of inflammatory bowel disease have been reported. Although this occurrence may be a mere unfortunate coincidence, there are sound pathophysiological reasons for such an event. The possibility that chronic inflammatory conditions, immunomodulator therapy, and infliximab can predispose to multiple myeloma and lymphoma is reviewed. We discuss in detail the only reported case of multiple myeloma arising in the setting of infliximab treatment for Crohn's disease. It is highly probable that infliximab therapy had a causal role in our patient developing multiple myeloma. The pathogenesis of multiple myeloma arising in the setting of infliximab therapy may be related to decreased apoptosis of plasma cell populations. Since it is possible that a causal association exists between infliximab therapy and multiple myeloma, additional screening measures may be required in patients with Crohn's disease on infliximab.