Over the last some years the increasing knowledge on the pathogenesis of Crohn's disease led to the development of a number of biological agents targeting specific molecules involved in gut inflammation, first of all TNF- α and its receptors. Infliximab, adalimumab and certolizumab have been successful in inducing and maintaining remission in Crohn's disease at both short and long term. This was recently confirmed by a Cochrane meta-analysis and also open label extension follow-up and cohort studies. Emerging new data however indicate that combination therapy with infliximab-azathioprine appears to have added benefit in inducing steroid-free remission and mucosal healing than either infliximab or azathioprine alone in azathioprine-naïve patients with early disease. Similarly the combination of steroids induction and infliximab was efficacious in luminal Crohn's disease. In contrast, there seems to be no synergism between methotrexate and infliximab. It is also less clear whether it is beneficial to use short or long-term infliximab-azathioprine combination in patients who previously failed therapy with azathioprine. In contrast, combination may potentially be associated with increased risk for infection and cancer. In case control-studies, especially the combination of steroids and anti-TNF and older age increased the risk for infectious complications, while scattered case reports point to the potentially increased risk of a rare form of non-Hodgkin's lymphoma (Hepatosplenic T cell lymphoma) with the use of azathioprineanti- TNF combination. The aim of this review is to summarize the benefits and risks for the use combination therapy with TNF-α inhibitors in the treatment of Crohn's disease.