The aim of this study was to enhance our understanding of the relationship between affect-related dispositions to rash action, negative urgency (NU: the tendency to act rashly when in a negative mood), positive urgency (PU: the tendency to act rashly when in a positive mood) and level of nicotine dependence symptoms by examining how the two traits transact with affect-related smoking expectancies. Based on the Acquired Preparedness model of addictive behaviors, we hypothesized that the relationship between PU and level of nicotine dependence would be mediated by positive affect smoking expectancies. We also hypothesized that the relationship between NU and level of nicotine dependence would be mediated by negative affect reduction expectancies. We studied 139 college-aged smokers and found support for this model; positive affect expectancies for smoking mediated the relationship between PU and level of nicotine dependence symptoms. Negative affect reduction smoking expectancies mediated the relationship between NU and level of nicotine dependence. The clinical implications of this research suggest that prevention/intervention programs should include substance-free activities as reinforcement and as ways to deal with extreme positive and negative mood.