In the mouse, maturing oocytes and zygotes until the late 1-cell stage are transcriptionally inert. The development of early preimplantation embryos, including reprogramming of differentiated germ cells into totipotent embryos, is regulated by the translation of mRNAs in oocytes preliminarily stored during oocytogenesis (maternal mRNAs). In the period of oocyte to zygote transition in mammals, the translational promotion or repression of maternal mRNAs does not start in unison. For example, a set of maternal mRNAs that are translationally quiescent in the growing stage become translated after the start of maturation and/or fertilization, but another group of maternal mRNAs that are actively translated in the growing stage become inactivated during maturation. This selective and temporal translational profile of maternal mRNAs seems to be regulated by RNA-binding proteins that bind to maternal mRNAs and decide the timing of their entry into the ribosome and by special short sequences in maternal mRNAs that recognize specific RNA-binding proteins. In this review, we focus on the mechanisms that modulate the profile of post-transcriptional regulation in the period of oocyte to zygote transition in mammals.