The purpose of this investigation was to compare the shear bond strengths of four dentinal adhesives. The shear bond strength was determined by testing specimens in the Instron universal testing machine at a crosshead speed of 0.5 mm/min. Scanning electron microscopic observations between × 10 and × 5000 magnifications demonstrated that the majority of the fracture patterns were either, in dentin or composite resin with Scotchbond 2 and near the adhesive interface with Tenure, Dentin Adhesit, and Gluma. A Tukey range statistic at P = .05 indicated no statistically significant difference between the bond strengths of Gluma and Dentin Adhesit; the bond strength of Tenure was significantly greater than that of Gluma or Dentin Adhesit, but less than that of Scotchbond 2; and the shear strength of Scotchbond 2 was significantly greater than that of Gluma, Dentin Adhesit, or Tenure.