These experiments were undertaken as a basic study to understand the role of cumulus cell on in vitro maturation and fertilization process with identifying the cumulus cell-secreted proteins. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) and fast protein liquid chromatography(FPLC), the proteins of cumulus cells were identified. The results obtained in these experiments were summarized as follows ; 1. When the proteins secreted from cultured cell for 30 hours were separated by SDS-PAGE, there were a major band (>94,000) and other minor 2 bands with molecular weight ranging 30,000∼67,000 dalton. 2. In addition, the fractionations of these proteins by FPLC were idirectly shown that three bands were hyaluronic acid, chondroitin sulfate, and heparin.