This experiment was studied of the peritoneal fluid when it was used for culture fluid of fertilized ova of rabbits and it was cultivated in vitro. The peritoneal fluid also can be gained much from the superovulated rabbits. The results were as follow. 1. When 2, 4, 8 cell stage ova of rabbit were cultivated in peritoneal fluid at 37℃ for 48 hours each ova was developed as much as 78.1%, 83.3% and 91.7%, and these records were superior to the useing of blood serum. 2. When 2 cell stage ova of rabbit was cultivated in peritoneal fluid, 88% of ova were rapidly growth for morula stage and 24% became blastcyst stage. These records are nearly same to the records in blood serum. At these points, the rabbit peritoneal fluid can be used effectively for ova culture fluid.