This experiment explored the influence of mood on the organisation of both the self-concept and information about a known other. Multidimensional scaling techniques were used to model the structure of both representations held by individuals experiencing happy, sad, and neutral moods. The selfconcept features of neutral mood participants were primarily organised along achievement- and affiliation-oriented dimensions. In contrast, the selfconcepts of happy and sad participants were less complex; self-features were primarily organised with respect to a simple valence dimension. In all three mood conditions, individuals' conceptions of a known other were predominantly organised with respect to a general valence dimension; however, as with the representation of self, the presence of a happy or sad mood accentuated the use of the valence dimension for feature organisation. The implications of this modelling procedure for investigating self-concept structure and the effects of mood on cognitive organisation in general are discussed.