Indiana University-Purdue University Indianapolis (IUPUI) / Hypothalamic-pituitary-adrenal (HPA) axis dysfunction is found in heavy alcohol users. Negative urgency is a personality trait reflecting the tendency to act rashly in response to negative emotional states, and is associated with problematic alcohol consumption. The current study examined the relationship between negative urgency and HPA axis functioning following (1) negative mood induction and (2) intravenous alcohol administration among heavy social drinkers (proposed n = 40). I hypothesized the following: (1) Negative mood induction would result in an increase of cortisol release as compared to neutral mood induction; (1a) Negative urgency would be related to increased cortisol release in response to negative mood induction; (1b) Negative urgency would partially mediate the relationship between mood induction and cortisol release; (2) Acute IV alcohol administration would result in increased cortisol levels in the neutral mood condition, but decreased cortisol levels in the negative mood condition; and (2a) Negative urgency would be related to the suppression of cortisol release in the negative mood condition in response to acute IV alcohol administration. Repeated measures analyses of variance, the PROCESS macro, and paired samples t-tests were used to examine study hypotheses. Hypotheses were largely unsupported. Writing mood induction procedures reduced salivary cortisol levels in negative mood (t(35)= 2.49, p= 0.02) and there was a trend decrease in neutral mood (t(35)= 1.87, p= 0.07). Alcohol administration also reduced salivary cortisol levels in both negative mood (t(35)= 3.99, p< 0.01) and neutral mood (t(35)= 2.60, p= 0.01). However, salivary cortisol changes were no different than typical circadian patterns in response to mood induction (t(231)= 0.37, p=0.71) or in response to acute alcohol administration (t(231)= 0.44, p= 0.64). Negative urgency had a trend main effect on salivary cortisol level in response to acute IV alcohol administration, such that those higher in negative urgency were more similar to typical circadian patterns (F(19,28)= 1.59, p=0.13). This could serve as preliminary support for a psychological mechanism for the alcohol sensitivity hypothesis. Overall these findings suggest the current study failed to sufficiently manipulate salivary cortisol levels. Future studies should consider methodological techniques when exploring these relationships, including IV compared to oral alcohol administration, mood compared to stress manipulations, and cortisol compared to other HPA axis biomarkers.