This study assessed comparatively the tensile bond strengths to dentine of four resin dentine bonding agents. Flat surfaces were produced in the occlusal dentine of human third molars, finished with 600-grit paper and prepared for bonding to Silux Plus composite with Gluma, Prisma Universal Bond 2, Scotchbond 2 and Tenure. After 24 hours in water and 250 thermal cycles, the specimens were loaded in tension to failure on an Instron machine. There were 20 specimens in each test group. An analysis of variance and Duncan's test showed that the bond strengths of Scotchbond 2 (22.8 +/- 7.2 MPa) and Prisma Universal Bond 2 (20.1 +/- 7.8 MPa) were similar but significantly higher than those of Tenure (14.3 +/- 5.3 MPa) or Gluma (12.3 +/- 6.4 MPa). A Weibull analysis confirmed the superiority of Scotchbond 2 and Prisma Universal Bond 2. Scotchbond 2 and Prisma Universal Bond 2 specimens failed either in an adhesive-cohesive mode, or cohesively through the composite or the dentine. It was concluded that Scotchbond 2 and Prisma Universal Bond 2 are effective and are the dentine bonding agents of choice.