Odor is a strong instrument to evoke emotions and memories. This opens numerous potential possibilities in the area of marketing. The effects on customers triggered by ambient scent are rather unexplored. Therefore, this paper aims to find out how incongruent and congruent ambient scent as atmospheric stimuli is affecting consumers’ behavior and their quality perception. The study is based on a modified S-O-R (Stimuli-Organism-Response) model from which assumptions were developed and a questionnaire was designed. The field study, with 612 respondents in total, was conducted in a supermarket and sports store where the environment was non-scented, congruent scented and incongruent scented. The results show that customers were positively influenced in their satisfaction and performance behavior with the congruent scent, as well as that the quality perception was evaluated more positively in a congruent scented environment. Nevertheless, it is noteworthy to declare, that incongruent scent gives the customer a feeling of less crowdedness. Thus, ambient scent can influence customers, but the choice of the right scent is an essential decision and depends on the respective store type.