Purpose: The author performed experiments on the microhardness and the marginal fitness of composite resins after polymerizing 4 kinds of composite resins on MOD standard specimens. Methods: For this study, in order to compare the microhardness and the marginal fitness of 4 kinds of composite resins. Results: The results are as follows. 1. In case of the microhardness, Tescera scored the highest among the four kinds of composite resins. 2. In case of the marginal fitness, Premise Indirect scored the highest. However, there was no statistically significant difference, all staying in clinically practical range. 3. Considering the above results, among the four kinds of composite resins, the author advises to use Tescera during teeth restoration which scored the highest in the micro- hardness. Conclusion: Conclusion: All of the composite marginal fitness were within the clinically useful range.