Repair to concrete structures often involves breaking out cracked concrete and replacing this and areas of spalling with a mortar or concrete. Adhesion of the new patch to the original concrete is generally considered to be an important criterion in judging the success of the repair. In recent years, the pull-off test method has gained favour as an in situ method of assessing the tensile adhesion strength. On the basis of an extensive programme of tests, this paper outlines the factors which affect the test and describes an appropriate scheme for acceptance testing of patch repairs. (A)