Previous research suggests that cortisol can affect cognitive functions such as memory, decision making and attentiveness to threat-related cues. Here, we examine whether increases in cortisol, brought on by an acute social stressor, influence threat-related decision making. Eighty-one police officers completed a standardized laboratory stressor and then immediately completed a computer simulated decision making task designed to examine decisions to accurately shoot or not shoot armed and unarmed Black and White targets. Results indicated that police officers who had larger cortisol increases to the social stress task subsequently made fewer errors when deciding to shoot armed Black targets relative to armed White targets, suggesting that HPA activation may exacerbate vigilance for threat cues. We conclude with a discussion of the implications of threat-initiated decision making.