Techniques for evaluating the adhesion of thin metal films deposited onto flexible substrates have been reviewed. The use of the scratch test for this application has been examined, and a correlation between scratch-test results and actual failure during simulated usage is presented. It was found that aluminum adheres more strongly to Teflon than does silver for the specimens tested and that the failure modes for these two metal–dielectric interfaces are substantially different. The shearing stresses required to remove the films from their substrates have been calculated and are in close agreement with previously reported data on rigid substrates.