To determine the impact of multiple micromanipulation procedures for preimplantation genetic diagnosis (PGD) on embryo development, a retrospective analysis was performed of 9,925 embryos (862 PGD cycles), which were compared with 28,126 nonbiopsied embryos (2,751 consecutive intracytoplasmic sperm injection [ICSI] cycles) from the same time period. Because fertilization rates, the proportion of embryos with > or = 6 cells on day 3, and blastocyst rates were similar in the PGD and control groups, we conclude that multiple micromanipulations on oocytes and embryos can be performed safely for PGD.