In this study, we examined the effect of trauma exposure on substance use behaviors, specifically tobacco and alcohol use, in a group of 84 individuals who sought supportive services after the 1995 Oklahoma City bombing. A self-report instrument was used to assess demographics, sensory exposure, injury, interpersonal exposure through relationship with victims, peritraumatic reaction, grief, posttraumatic stress, worry about safety, functional impairment, and changes in smoking and drinking. Those who reported increased smoking had higher scores on peritraumatic reaction, grief, posttraumatic stress, worry about safety, and trouble functioning. Those who reported increased alcohol intake had higher scores on injury, peritraumatic reaction, grief, posttraumatic stress, worry about safety, and trouble functioning. Sensory exposure and interpersonal exposure were not significantly different between those with and without increased smoking or drinking. Although no causal relationship can be assumed, our findings indicate an association of grief and posttraumatic stress with increased substance use behaviors in disaster victims.