We predicted the success or failure of fertilization by the presence or absence of a second polar body 6 hours after insemination, and we performed intracytoplasmic sperm injection (ICSI) for oocytes that did not produce a second polar body to investigate the efficacy of such rescue ICSI. Cases in which ICSI was performed as scheduled after oocyte collection were classified together as the ICSI group. Those in which the second polar body was confirmed in at least half of the oocytes 6 hours after insemination by in vitro fertilization (IVF) were classified as the IVF group, and those in which the second polar body was not confirmed in at least half of the oocytes 6 hours after insemination and on which ICSI was thus performed were classified as the rescue ICSI group. The fertilization rates in the ICSI group, IVF group and rescue ICSI group were 73.8%, 75.4% and 69.0% without significant differences. Pregnancy rates were 41.0%, 41.0% and 29.8%, in the respective groups without significant differences. Our results strongly suggest that cancellation of embryo transfer is avoided by rescue ICSI when IVF results in all unfertilized oocytes.