Single blastocyst transfer was performed in 306 IVF patients during 2002 to August 2003 in women younger than 39 years of age with at least five fertilized oocytes. Viable pregnancy rate per single blastocyst transfer was 40.7% during 2002 and 47.6% during 2003 (amounting to 35% of all IVF cycles), which in our experience are acceptable results. Single blastocyst transfer was performed in 306 IVF patients during 2002 to August 2003 in women younger than 39 years with at least five fertilized oocytes. Viable pregnancy rate per single blastocyst transfer was 40.7% during 2002 and 47.6% during 2003 (amounting to 35 % of all IVF cycles), which in our experience are acceptable results.