Systematic studies of cell divisions at the beginning of mammalian life are of fundamental importance for our understanding of embryonic development and fertility. However, in the past the challenges of in vitro embryo culture and the embryo's pronounced light sensitivity have precluded a detailed investigation of preimplantation cell divisions. This protocol is based on recent technological breakthroughs in inverted light microscopy tailored for mouse embryology. Due to its reduced light dose, and therefore low phototoxicity, as well as higher acquisition speed, light-sheet microscopy allows extended 3D time-lapse imaging of early embryonic development with very high spatial and temporal resolution. This imaging approach enables imaging of key subcellular structures during the critical cell cycles from the zygote up to the blastocyst stage, with a resolution that allows automatic computational tracking and quantitative analysis of the dynamics of mitotic organelles.