Based on the mood-behavior-model (Gendolla, 2000), this study tested the idea that moods only have effects on effort mobilization in settings that directly call for this and in which people can thus use their moods as task-relevant information. Fifty university students were randomly assigned to a 2 (Mood:negative vs. positive) x 2 (Memorizing: intentional vs. incidental) x 2 (Time: mood induction vs. task performance) mixed model design. Effort mobilization was operationalized as systolic blood pressure (SBP) reactivity. As expected, in the intentional-memorizing condition, SBP reactivity was stronger in a negative mood than in a positive mood. Mood had no impact in the incidental-memorizing condition, which did not call for effort mobilization.