The purpose of this study was to evaluate bonding durability for the various generation of dentin bonding agents. Eight dentin bonding agents were tested. One hundred twenty non caries extracted human molars were used. Microleakage and microtensile bond strength (MTBS) test were performed. The specimens were bonded with dentin bonding adhesive systems according to manufacturer"s instruction. The specimens were cut to stick-shape and stressed in tension at a crosshead speed of 1 ㎜/min. Results were analyzed using Weibull analysis. Scotchbond MP (3M ESPE) showed the least microleakage, and the other groups showed the similar microleakage. The MTBS of experimental groups varied from 30.80 to 39.54 MPa. Single Bond (3M ESPE) had the highest Weibull modulus (6.543) and Clearfil S3 Bond (Kuraray) had the lowest value (3.832). The simplified dentin bonding adhesives (7th generation) showed acceptable bond strength in comparison with the three-step adhesives (4th generation).