Received May 03, 1997
Accepted June 17, 1997

Introduction: The ultrarapid method is a simple and low cost technique to human embryos cryopreservation. This paper shows our experience using this technique and the success after ultra rapid modified method. Material and methods: A total of 60 patients whose had exceeding embryos after "in vitro fertilization" (IVF) and for intracytoplasmic sperm injection (ICSI) were divided in two groups to freeze embryos. Group I: 33 patients frozen and thawed 145 embryos with ultrarapid method and only one step thawing method. After thawed, the embryos were cultured for 1 hour and embryos with at least one intact blastomere were transferred. Group II: 36 patients frozen and thawed 205 embryos with ultrarapid method and three steps thawing method. After thawed, the embryos were cultured for 24 hours and embryos which following development were transferred. Results: The age of patients was 31.71±4.13 in Group 1 and 31.42±4.29 in Group II. did not differ significantly (0.64). The mean of embryos transferred was 3.09±1.63 in Group I and 3.23±1.27 in Group II. It did not differ significantly between the number of embryos transferred (p=0.46). The pregnancy rate per transfer was significantly higher in Group II (p=0.022) compared to Group I 31.8% versus 6% respectively. Conclusion: Ultrarapid modified method as well as selection rule to transfer embryos are proceeding effective for human cryopreservation programo