The purpose of this study was to develop an explanatory model of impulse buying that addressed antecedents of impulse buying. For this research, impulse buying was defined as an unplanned, hedonic purchase that follows a sudden urge. Impulse buying reflects a rapid decision in response to a stimulus reflecting little cognitive consideration and disregard for consequences. Donovan and Roissiter (1982) suggested that a pleasant store environment (S) causes shoppers’ positive emotional states (O) and this in turn, yields shoppers’ approach behaviors (R), that is, a desire to remain in a store and explore its offerings. Applying this idea to impulse buying suggests that there are environmental stimuli in a store that could impact shoppers’ impulse buying tendencies and that individual shopper characteristics could moderate the influence of these environmental influences. Therefore, environmental influences on impulse buying and personal characteristics of impulse buyers were examined in a modified stimulus-organism-response (S-O-R) framework. Environmental stimuli (i.e., ambient factor, aesthetic factor, layout factor, excitement factor, promotion factor, sales associate factor) were predicted to influence shoppers’ mood and subsequently, contribute to impulse purchases. In addition, specific shoppers’ characteristics (i.e., lack of control, extroversion, innovativeness, hedonic consumption tendency, impulse buying tendency) were predicted to moderate the relationship between environmental stimuli and shopper’s impulse purchases. Data was collected from a convenience sample of 299 undergraduates at two Midwestern universities in the United States. Participants were asked to complete the questionnaire immediately after they had gone shopping for apparel, shoes, or accessories. Participants answered questions on their purchase, perceptions of the store environment, mood, and personal characteristics. Most of the participants were females (93.3%), aged between 18 and 23 (92.6%). They were never married (95.8%) and Euro American (83.5%). Participants’ impulse buying reflected pure impulse buying (28.3%), suggestion impulse buying (20.3%), reminder impulse buying (34.1%), and non-impulse buying (17.4%). Approximately 40 percent of the participants classified their purchase as either very impulsive or impulsive. The prices of the items that participants purchased ranged from $1 to $319 (m=$ 45). Participants purchased an item of apparel (65%), shoes (21%) or accessories (14%). Hypothesis 1 predicted that specific store environmental stimuli are associated with the perceived impulsiveness of a purchase. Only the relationship between store layout and impulsiveness of purchase was significant (t=3.30, p<.01) with a path coefficient of .20. Hypothesis 2 posited that shopper’s mood will be attributed to specific store environmental stimuli. The ambience, excitement, and sales associate variables had significant relationships with participants’ mood. The path coefficient was .27 (t=4.77, p<.01) for the relationship between store ambience and mood, .29 (t=4.83, p<.01) for the relationship between store excitement and mood, and .18 (t=3.11, p<.01) for the relationship between sales associate and mood. Hypothesis 3 proposed that the perceived impulsiveness of a purchase is associated with shopper’s mood. There was a significant relationship (t=4.01, p<.01, path coefficient of .24). The more positive the reported mood of participants, the more they perceived their purchases as impulsive. Hypothesis 4 predicted that specific participant’ characteristics (i.e., lack of control, extroversion, innovativeness, hedonic consumption tendency, and impulse buying tendency) would moderate relationships between store environmental cues and the perceived impulsiveness of their purchases. A specific characteristic of participants, lack of control moderated the relationship between store layout and the perceived impulsiveness of their purchases. Our findings supported the proposed research framework, the stimulus-organism-response (S-O-R) model; positive emotional responses (O) resulted in approach behaviors (R), an impulse purchase. As reflected in the model, specific store environmental stimuli (S) such as ambiance, excitement, and sales associates were a significant positive influence on shoppers’ mood during shopping. The findings supported the existence of a direct relationship between a store environmental stimulus (S), store layout and a consumer approach behavior (R), impulse buying. Store aesthetics and promotion were not associated with either participant’s mood or impulse buying. A personal characteristic, lack of control moderated the relationship between store layout and impulse buying. Clearly our findings point to the importance of store layout when shopping for fashion related items. In addition, providing entertainment that enhances the hedonic and the experiential value of the store experience can influence young adult consumers. Since consumers’ mood at the point-of-purchase may be influenced by interactions with sales associates, sales associate training to enhance the consumer experience should not be neglected.