The purpose of this project was to test the in vitro bond strength of three dentinal bonding agents to primary dentin. Scotchbond 2, All-Bond, and Amalgambond were applied to 63 teeth according to manufacturer's instructions. Valux composite resin was placed in a cylindrical matrix and light cured to the treated dentin. After they were thermocycled for approximately 800 cycles between 6 degrees C and 60 degrees C, the specimens were mounted in stone and placed in an Instron universal testing machine. They were placed under continuous load until failure. Fracture was at the dentin-bonding agent interface for all materials tested. Incisor bond strength was significantly stronger than molar bond strength for all three materials. Materials analysis revealed that the mean bond strength for Scotchbond 2 (6.99 MPa) was significantly different from those of All-Bond (13.01 MPa) and Amalgambond (13.03 MPa).