Objectives: To examine whether expectations regarding the benefits of exercise influence perceived mood changes post-exercise, by virtue of memory biases. Design: 2 x 2 Mixed design with 40 participants assigned to either exercise or non-exercise conditions. Pre-activity mood estimate (actual vs. retrospective) was measured within-groups. Mood change was assessed using the Incredibly Short Profile of Mood States (Whelan, Epkins, & Meyers, 1990). Method: The exercise group completed a 10-min jogging session, with current mood assessed pre- and post-activity. Additionally, participants were asked, post-activity, to retrospectively assess their pre-activity mood state. A non-exercise control group completed a 10-min cognitive task. Results: Findings concur that 10-min bouts of exercise can beneficially impact upon mood. In addition, this effect was augmented by biased recall of pre-exercise mood. Conclusions: Individuals' perception of mood enhancement can be augmented by reconstructive memory biases, suggesting that expectations regarding the benefits of exercise are crucial for maximising perceived mood enhancement. (C) 2010 Elsevier Ltd. All rights reserved.