Microvesicles (MVs) are released by different cell types and may remain in the extracellular space in proximity of the cell of origin or may enter the biological fluids. MVs released by tumor cells are detectable in patients with cancer and their number in the circulation correlates with poor prognosis. Recent studies demonstrated that MVs may act as mediator of cell-to-cell communication thus ensuring short- and long-range exchange of information. Due to their pleyotropic effects, MVs may play a role in the prothrombotic state associated with cancer as well as in cancer development and progression. It has been recently shown that MVs may induce epigenetic changes in target cells by transferring genetic information. This finding suggests that tumor and stromal cells may talk each other via MVs to establish a favorable tumor niche and to promote tumor growth, invasiveness and progression. Moreover, MVs contain genetic material under the form of mRNA and microRNA, that may allow an easy screening for cancer genetic markers and offer new diagnostic and prognostic information. This review presents an overview of the many biological actions of MVs and of the potential role of MV-mediated exchange of genetic information among cells in tumor biology.