Oocyte maturation is accompanied by a transition from mRNA stability to instability. We investigated the role of DCP1A and DCP2, proteins responsible for mRNA decapping, in mRNA destabilization during mouse oocyte maturation. siRNA-mediated knockdown of both Dcp1a and Dcp2 transcripts prior to initiation of maturation inhibited the maturation-associated increase of DCP1A and DCP2, stabilized a set of maternal mRNAs that are normally degraded during maturation, and inhibited development beyond the 2-cell stage, likely a consequence of failure to activate fully the zygotic genome. Overall design: Total RNA from 30 MII eggs was used in each sample. Three independent biological replicates were analyzed for each condition.