The lack of an accepted measure of awareness has made claims that accurate decisions can be made without awareness controversial. Here we introduce a new objective measure of awareness, post-decision wagering. We show that participants fail to maximize cash earnings by wagering high following correct decisions in blindsight, the Iowa gambling task and an artificial grammar task. This demonstrates, without the uncertainties associated with the conventional subjective measures of awareness (verbal reports and confidence ratings), that the participants were not aware that their decisions were correct. Post-decision wagering may be used to study the neural correlates of consciousness.