This study was designed to assess the relationship between self-report and psychophysiological responses to fear appeals and behavioral changes elicited by these. Ninety-two subjects watched one of four messages that varied in level of threat (high vs. low) and efficacy (high vs. low). Concomitantly, psychophysiological measures (heart rate and skin conductance) were registered. Perceived threat and efficacy varied according to the characteristics of the message. High-threat messages elicited significantly different levels of autonomic arousal than low-threat messages. Following of behavioral recommendation was higher among subjects who were exposed to the high threat/high efficacy stimulus, those who reported high perceived threat, and for those who showed an autonomic response pattern related to the facilitation of attentional processes.