Adult female mice of Swiss albino strain were superovulated by intrapeıitonal injection of PMSG and HCG 48 hours apart. They were killed 16 hours after injection of HCG and their eggs were recovered under warm oil in a plastic dish containing 0.4 ml of ineubatian medium.

Sperms recovered from cauda epididymis of adult males of the same strairi were suspended in a medtum and incubated at 37° C under % 5 CO₂ in air for 1.5-2 hours before they were used for insemination. The ineubatian medium was THY medium containing glucose, sodium pyruvate, bovine albumtn and antibiotics.

At the time of insemination, a drop of sperm suspension (10-20 µl) was added to the medium contatning egg clot. Eggs and sperms were incubated in ineubatian medium for 6 hours. In the fırst group, fertilized eggs were left into the same medium. In the second group they were transferred to the development medium (Modifıed Whitten's) without sodium lactate and incubated until they were examtned under stereo-microscope.

As a conclusion, in this study fertilized eggs and 2-cell stage embıyos were obtained but further stage of embıyos (morulae, blastocyst) couldn't be reached.