This study investigated the effect of microwave treatment on the shear bond strength of the denture tooth to acrylic resin adhesion, when the glossy ridge laps were unmodified, abraded, grooved, or etched by monomer. Eighty specimens (n=10) were polymerized in a hot bath at 74C for 9 hours, and deflasked after flask cooling. Specimens were soaked in 150mL of distilled water and submitted to microwave treatment in a domestic microwave oven calibrated at 650W for 3 minutes. Control specimens were not microwave treated. The shear bond strength test was performed in an Instron machine with a cross-speed of 1mm/minute. The ultimate fracture load value was transformed into shear bond strength as a function of the bonding area. Collected data were submitted to ANOVA and Tukey's test (alpha=.05). Treatment by microwave energy significantly decreased (p <.05%) the shear bond strength values in all ridge lap conditions used for the denture tooth/resin adhesion.