This study evaluated the influence of irradiation on the dentin bond strength. Sixty irradiated and sixty nonirradiated human third molars were used. The irradiation dose of 60 Gy was fractionally applied over six weeks (2 Gy/day, 5 days/week). All teeth were prepared in a special manner allowing the simulation of intrapulpal pressure and dentin perfusion. Dentin specimens with a thickness of 2.0 mm were obtained under standardized conditions. The specimens were randomly assigned to four experimental groups. Tensile bond strength of four different dentin bonding agents (ScotchbondTM 1, Solobond Plus®, Prime&BondTM 2.1 and Syntac®) was evaluated using an Instron Universal testing machine. Pairwise comparison did not showed any significant differences between the irradiated and nonirradiated groups. The influence of the different dentin adhesives was significant (P = 0.0001; ANOVA). Compared to the other dentin adhesive agents, the use of ScotchbondTM 1 resulted in a significantly higher tensile bond strength (P Palabras clave: irradiation, dentin adhesive, bond strength, dentin