Purpose: To compare the efficacy of freezing embryos at the 2 pronuclear stage vs multi-cell stage using a simplified freezing protocol with a one-step removal of the cryoprotectant. Methods: A retrospective analysis was performed. Survival, delivered pregnancy and implantation rates were compared in transfers of all embryos frozen at 2 pronuclear stage (2PN) or all embryos frozen at multi-cell stage. The results were further stratified and compared according to the number of high quality embryos transferred. Results: In all categories despite comparing similar numbers and quality of embryos transferred there was a significantly higher survival rate of 2PN embryos. Significantly higher delivered pregnancy and implantation rates were seen with 2PN vs multi-cell embryos when there was only one or two embryos with ≥6 blastomeres and <25% fragmentation, and a trend for higher delivered pregnancy rates when there were three top quality embryos transferred. Conclusions: When given the option it is preferable when using this simplified freezing and thawing protocol to freeze at the 2PN stage.