Perpetrating romantic infidelity is discrepant with how most individuals see themselves and theoretically should produce cognitive dissonance. Accordingly, perpetrators of infidelity should experience symptoms of dissonance (e.g. self-concept discrepancy, psychological discomfort, poor affect) and employ tactics that reduce these symptoms (e.g. trivialization). These hypotheses were tested in four experiments. In each experiment, participants were given bogus feedback indicating that they had acted either faithfully or unfaithfully during a prior romantic relationship (this manipulation was evaluated in experiment 1). Participants who received unfaithful feedback reported higher levels of self-concept discrepancy, psychological discomfort, and poor affect (experiments 2 and 4) and trivialized to a greater extent the importance of their ostensive infidelities (experiments 3 and 4). Experiment 4 further showed that trivialization significantly reduced self-concept discrepancy and psychological discomfort but not poor affect. These results are generally consistent with the view that infidelity is a dissonance arousing behavior and that perpetrators of infidelity respond in ways that reduce cognitive dissonance.