This study was undertaken to evaluate the degree of the marginal leakage of composite restoration with 3 brands of dental adhesives by means of the dye penetration at the enamel and dentinal margins. 150 cavities of class V were prepared on the buccal and lingual surfaces of 75 extracted anterior and premolar teeth, which were devided into 3 groups. The cavities were filled with composite resin, Silar$^{(R)}$ (3M) and Heliosit$^{(R)}$ (Vivadent) after application of the dental adhesives, specifically Scotchbond$^{(R)}$ (3M) which is essentially composed with halophosphorus ester of Bis-GMA, Dentin Adhesit$^{(R)}$ (Vivadent) which is polyurethane resin, and Enamel Bond$^{(R)}$ (3M) which is a product of Bis-GMA with low viscosity at internal surfaces and margins of the cavities. All specimens were immersed in $37^{circ}C$, 0.5% methylene blue solution for 24 hours after thermocycling at $4^{circ}C$ and $60^{circ}C$, embedded in acrylic resin, and sectioned with diamond disk into two parts. The sectioned specimens observed with the light microscope. The following results were obtained: 1. The group filled with Scotchbond$^{(R)}$-Silar$^{(R)}$ the other two groups at the enamel margins. 2. No significant difference in the degree of the marginal leakage had appeared between Dentin Adhesit$^{(R)}$-Heliosit$^{(R)}$ group an d Enamel Bond$^{(R)}$-Silar$^{(R)}$ group at the enamel margins. 3. Severe marginal leakage with penetration of dye to the floor of cavity had appeared from the all three groups and no significant difference in the degree of marginal leakage existed between the three groups at the dentinal margins.