This study was carried out to investigate the effect of morphology of oocytes, kinds of media, cysteine and myo-inositol supplementation on IVM rate of porcine oocytes. Cumulus- enclosed oocytes were incubated in maturation NCSU-23 and TCM-199 medium with supplementation with 3, 5, 10, 20 mM myo-inositol and 0.05, 0.1, 0.5, 1.0 mM cysteine. 1. When classified by morphology, excellent, good and fair of cumulus-enclosed oocytes were incubated for 48 hrs and the IVM rate were $14.2{pm}3.7%{sim}58.7{pm}4.0%$, respectively. The rate were greater in oocytes with excellent cumulus cells than those without cumulus cells. 2. The IVM rate of oocytes cultured in TCM-199 and NCSU- 23 medium supplementation or non-supplementation with 1.0 mM myo-inositol were $7.5{pm}4.5%,;45.0{pm}4.8%;and;4.4%,;42.5{pm}4.2%,;18.0{pm}5.2%$, respectively. Supplementation with myo-inositol significantly increased the IVM rate of oocytes. 3. The IVM rate of oocytes cultured in NCSU-23 medium supplementation of 3, 5, 10, 20 mM myo-inositol for 48 hrs were $47.5{pm}4.5%,;57.5{pm}4.2%,;62.5{pm}4.9%,;50.0{pm}5.2%$, respectively. The IVM rate of oocytes in NCSU-23 medium supplemented with 10 mM myo-inositol were significantly increased compared to control ($42.5{pm}4.0%$). 4. The IVM rate of oocytes cultured for 48 hrs in NCSU-23 media supplement with 0.3, 0.5, 1.0, 2.0 mM myo-inositol were $50.0{pm}4.5%,;62.5{pm}4.2%,;52.5{pm}4.9%,;45.0{pm}4.2%$, respectively. The IVM rate of oocytes in NCSU-23 medium supplemented with 10 mM cysteine were significantly increased compared to control ($42.5{pm}4.0%$).