Dendritic cells (DC) are central to the immune system because of their role in antigen presentation leading to either tolerance or immunity among cells of the adaptive immune response. It is becoming increasingly evident that DC show extensive plasticity in terms of their origin and function, giving rise to a number of subsets represented differentially in all lymphoid organs. This article considers the tolerogenic capacity of murine DC and draws a distinction between DC that induce tolerance in the immature state and immunity in an inflammatory context, and those that act as regulatory cells inducing immunosuppression in the presence of inflammation.