Existing research has established the effects of mood on processing of clearly mood-elevating proattitudinal messages and clearly mood-threatening counterattitudinal messages (i.e., mood-relevant messages). Little is known, however, about mood effects on processing of less mood-elevating proattitudinal messages and less mood-threatening counterattitudinal messages (i.e., mood-irrelevant messages). The present research tested hypotheses regarding processing of mood-irrelevant messages based on a mood-congruent expectancies approach. Specifically, two studies were conducted in which prior attitudes were measured (Study 1) or manipulated (Study 2). As predicted, results showed higher scrutiny in negative mood given a proattitudinal message and in positive mood given a counterattitudinal message than in negative mood given a counterattitudinal message and in positive mood given a proattitudinal message. Discussion focuses on implications regarding the accumulated literature, different accounts proposed to understand mood effects on processing effort, and further research.