The purpose of this study was to investigate the effects of acute exercise mimicking boxing on affect and mood states. In a randomized crossover design, 16 adults (35.8±6.6 yrs) underwent both a boxing exercise program based on shadow boxing (Boxing) as well as a boxing program combined with a focus mitts workout (pad work) (Boxing+Mitts). The Waseda Affect Scale of Exercise and Durable Activity (WASEDA) and the Profile of Mood States-Brief Form (POMS-Brief) were administered before and after both exercise programs. There were no gender differences in any psychological scales before and after the programs as well as in heart rate during exercise. The Boxing+Mitts program tended to show a lower exercise intensity, defined as the percentage of the average heat rate reserve (HRR), than the Boxing program (40.4±13.3 vs. 50.4±17.5%HRR, p <0.10). However, both programs were considered to give a moderate level of exercise intensity on average, which is regarded as the minimum intensity required to improve individual cardiorespiratory fitness. The Boxing program significantly improved all 3 scales of negative affect, positive engagement and tranquility assessed by the WASEDA. Moreover, the POMS-Brief showed an iceberg profile after the program, which was followed by significant decreases in the scores of tension-anxiety, depression-dejection, anger-hostility and confusion, and a significant increase in the vigor score. In addition, a composite score of total mood disturbance calculated by summing the subscale scores changed in a positive direction. The Boxing+Mitts program was shown to lead to similar changes in the WASEDA and POMS-Brief. However, no significant program×time interactions (by two-way ANOVA) were observed in any of the scales. These results indicate that acute boxing-style exercise programs would improve negative psychological variables and enhance both feelings of pleasant activation, as well as relaxation. A further study is warranted to explore whether any long-term (chronic) effects on mental health exist, and to compare these programs with other modes of exercise.