Cytokinesis, the mechanical process by which one cell becomes two, is essential to all life, be it single-celled bacteria or complex multicellular organisms like land plants or animals. It is now clear that new membrane must be added to the mother cell to accomplish the complete enclosure of the two daughters. In land plants, this is especially apparent because they accomplish cytokinesis with the cell plate, a structure newly assembled by addition of new membrane vesicles. This review will focus on what we know about the source of the vesicles that make up the cell plate membrane, the molecular machinery involved in assembling those vesicles, and just what those vesicles are carrying to the cell plate.