The overall purpose of this presentation is to review the overall effects of acute and chronic exercise on mental health outcome measures, such as decreases in anxiety, depression, and stress reactivity, and increases in positive mood state, self-esteem and cognitive functioning.  This review will primarily focus on results derived from large-scale epidemiological and experimental studies as well as meta-analytic reviews.  For each outcome measure, the overall effects will be presented, followed by a discussion of moderating variables and suggested explanations/mechanisms.  This review shows that overall exercise is related to, but does not cause, desirable changes in anxiety, depression, stress reactivity, positive mood, self-esteem, and cognitive functioning.  The overall magnitude of the effect of exercise on these variables ranges from small to moderate.  In all cases, these effects are statistically significant (p < .05).  Some of these relationships (e.g., cognitive functioning, self-esteem) have a greater likelihood of being spurious compared to other relationships (e.g., anxiety, depression).  Moderating variables for several of these outcome measures show that subjects who are extreme responders at the time of the pretest produce larger effects than subjects who are less extreme.  There also appears to be some consistency in chronic exercise producing larger effects than acute exercise, particularly if the chronic exercise program is longer than 12 weeks.  There is also no consistent evidence for moderating effects due to exercise intensity and duration and future research is recommended to examine this dose-response issue.  Finally, the issue of anaerobic training, particularly resistance training, needs to be addressed to determine why it has thus far shown inconsistent effects in reducing anxiety, but has been consistently effective in reducing depression and increasing positive mood and self-esteem.