•Dendritic cells internalize exogenous antigens for cross-presentation on MHC I.•MHC I cross-presentation allows immune surveillance of viral infection and cancers.•Dendritic cells utilize distinct and overlapping pathways for cross-presentation.•Phagosomes acquire cytosolic and ER-derived proteins for MHC-I loading of peptides. In order to get recognized by CD8 T cells, most cells present peptides from endogenously expressed self or foreign proteins on MHC class I molecules. However, specialized antigen-presenting cells, such as DCs and macrophages, can present exogenous antigen on MHC-I in a process called cross-presentation. This pathway plays key roles in antimicrobial and antitumor immunity, and also immune tolerance. Recent advances have broadened our understanding of the underlying mechanisms of cross-presentation. Here, we review some of these recent advances, including the distinct pathways that result in the cross-priming of CD8 T cells and the source of the class I molecules presenting exogenous peptides.