The present investigation involved the development of a psychobiologic profile of individuals who experience exercise-related mood-enhancement and those who do not. The sample (N=301) consisted of students participating in 10-week exercise classes at North Texas State University. All subjects completed pre-test inventories assessing various psychological (i.e., trait anxiety and depression, attitude toward physical activity, self-estimation of physical ability and attraction to physical activity, expectancies of health benefits from exercise, and self-motivation) and biological (i.e., aerobic capacity and body fat percentage) variables. Trait anxiety and depression were also assessed before and after the 10-week exercise program and state anxiety and depression were assessed on an acute basis on two separate occasions during the program. Multivariate analysis of variance and discriminant function analysis were employed to determine which variables maximally discriminated between individuals who experienced mood-elevations following exercise and those who did not enjoy such rewards. The hypothesis that these two groups of individuals differ significantly from each other was not upheld by the results; thus, an overall psychobiologic profile could not be developed. However, the data did reveal that individuals who held a more positive attitude toward physical activity for the purpose of health and fitness reduced their state anxiety and depression following exercise significantly more than individuals who held more neutral attitudes. The results also confirmed previous research that individuals initially high in trait anxiety and depression showed a significantly greater decrease in these traits than subjects scoring in the low-moderate range at the outset of the exercise class. Recommendations for future research are discussed.