Dengue virus (DENV) infects human immune cells in vitro and likely infects dendritic cells (DCs) in vivo. DENV-2 productive infection induces activation and release of high levels of chemokines and proinflammatory cytokines in monocyte-derived DCs (moDCs), with the notable exception of alpha/beta interferon (IFN-α/β). Interestingly, DENV-2-infected moDCs fail to prime T cells, most likely due to the lack of IFN-α/β released by moDCs, since this effect was reversed by addition of exogenous IFN-β. Together, our data show that inhibition of IFN-α/β production by DENV in primary human moDCs is a novel mechanism of immune evasion.