The purpose of this study was to evaluate the adaptability to tooth structure of light-cured glass ionomer cements. In this, study, class V cavities were prepared on the buccal surfaces of thirty extracted human premolar teeth, and they were randomly assigned into 3 groups with 10 teeth. The cavities of each groups were filled with the Fuji II LC(GC International Corp., Japan), Vitremer(3M Dental Products Division, U.S.A) and VariGlass VLC(Caulk/Dentsply Inc., U.S.A.). The specimens were immersed in 1% methylene blue solution and stored in 100% realtive humidity at $37^{circ}C$ for 5 days. And then, the specimens sectioned buccolingually. Degree of eke penetration at tooth--restoration interfaces were examined by magnifying glass at occlusal and gingival margin. The results were as follows : 1. On the occlusal margin, among the experimental groups, the group 2 showed the lowest microleakage($1.40{pm}1.17$) and the group 1 showed the highest microleakage($3.10{pm}0.99$). There was significant difference between group 1 and group 2(P<0.01). 2. On the gingival margin, among the experimental groups, the group 2 showed the lowest microleakage($2.50{pm}1.08$) and the group 1 showed the highest microleakage($3.50{pm}0.84$). But there was not significant. difference among the experimental groups(P>0.05). 3. The degree of microleakage at occlusal margin was less than gingival margin in all experimental groups.