These experiments were designed to investigate the effects of glycosaminoglycans(GAGs), which maybe produced by cumulus cells, on in vitro maturation process of bovine follicular oocytes. The rates of in vitro maturation of bovine oocytes were examined after incubating with the various concentrations of a hyaluronic acid, chondroitin sulfate, or heparin for 26 hours. The results obatained in these experiments were summarized as follows : 1. When the cumulus or removed oocytes treated with hyaluronic acid(200, 400, 800 and 1, 600$mu extrm{g}$/ml), the maturation rates of cumulus-removed oocytes were 48.6, 59.4, 68.4 and 61.3% respectively. Especially, at a concentration of 800$mu extrm{g}$/ml, the maturation rates(68.8%) of cumulus-removed oocytes were slightly lower than that(78.3%) of cumulus-enclosed oocytes. However, the treatment of hyaluronic acid showed significantly higher maturation rates compared to that(48.4%) of control group of cumulus-removed oocytes(p<0.05). Therefore, these results suggest thate hyaluronic acid had a beneficial effect on maturation of bovine follicular oocytes. 2. The maturation rate of cumulus-free oocytes treated with chondroitin sulfate(200, 400, 800 and 1, 600$mu extrm{g}$/ml) was 52.3, 56.1, 55.9 and 52.2% respectively. These rates were not different from those(52.9%) of control group. However, these rates in cumulus-free oocytes were significantly lower than that(79.0%) in cumulus-enclosed oocytes(p<0.01). Therefore, these results suggest that chondroitin sulfate do not affect on the maturation of oocytes. 3. In cumulus-free oocytes cultured with different heparin concentration, the maturation rates were ranged from 48.5 to 52.1%, showing no differencies from that(50.7%) of control group. However, these rates were significantly lower than 80.0% in cumulus-enlosed oocytes(p<0.01). 4. The nuclear maturaton of oocytes was increased by treatment of each of three glycosaminoglycans(hyaluronic acid, chondroitin sulfate, and heparin). In addition, the treatment of mixed together showed the significant additive effect. Hyaluronic acid was more effective than chondroitin sulfate and heparin were.