We examined the claim that the autobiographical Implicit Association Test (aIAT) can detect concealed memories. Subjects read action statements (e.g., "break the toothpick") and either performed the action or completed math problems. They then imagined some of these actions and some new actions. Two weeks later, the subjects completed a memory test and then an aIAT in which they categorized true and false statements (e.g., "I am in front of the computer") and whether they had or had not performed actions from Session 1. For half of the subjects, the nonperformed statements were actions that they saw but did not perform; for the remaining subjects, these statements were actions that they saw and imagined but did not perform. Our results showed that the aIAT can distinguish between true autobiographical events (performed actions) and false events (nonperformed actions), but that it is less effective, the more that subjects remember performing actions that they did not really perform. Thus, the diagnosticity of the aIAT may be limited.