Changes in mood following exercise are well documented; however, one particular limitation of research examining mood changes associated with exercise is that studies have not controlled for a possible expectancy effect. Given the difficulty associated with utilising a placebo control group in exercise settings and that no current questionnaires are available to measure beliefs concerning mood improvements during and after exercise, the present studies aimed to develop a suitable instrument for assessing these beliefs. In the first of these studies, 220 regular runners were respondents in developing the new scale. A logical approach to test construction, as proposed by Hase and Goldberg in 1967, produced two scales of acceptable reliability: a five-item subscale to measure beliefs concerning mood improvements during running (Cronbach alpha=.77) and a two-item subscale to measure beliefs about mood improvements following running (Cronbach alpha=.86). A second study, which involved the administration of these scales to 50 regular runners after a 60-min. treadmill run, indicated there were moderate associations between scores on these measures and mood changes during and after the run.