Based on the mood-behavior-model (MBM; Gendolla, 2000 ), it is proposed that moods play significant roles in two central processes of self-regulation: (1) The constitution of action preferences and (2) resource mobilization in instrumental behavior. Specifically, people's interest in behaviors that facilitate hedonic experiences depends on their momentary need for well-being and the perceived instrumentality of potential acts for satisfying this need. Resource mobilization is influenced by the use of moods as diagnostic information for demand appraisals, which in turn determine the intensity of effort and the persistence of behavior. A series of experiments that quantified effort as cardiovascular response has supported these predictions. The role of personality variables in the linkage between mood states and self-regulation is discussed.