The current study informed the definition of "excessive exercise" by examining relations between exercise behavior, eating-disordered behavior, and quality of life (QOL) in a community sample of women. Self-report measures of frequency of exercise, obligatory exercise and motivation for exercise, and of eating disorder psychopathology and QOL, were completed by 3,472 women aged 18-42 years who engaged in regular exercise. The extent to which exercise is intended to influence weight or shape and the degree to which guilt is experienced when exercise is postponed were the exercise variables most strongly associated with elevated levels of eating disorder psychopathology and reduced QOL. Subgroups of participants who reported exercising solely for weight and shape reasons (n = 322 [9.3%]), intense guilt after postponement of exercise (n = 136 [3.9%]), or both (n = 116 [3.3%]), had markedly elevated levels of eating disorder psychopathology. There was no association between excessive exercise and reduced QOL after the effects of eating disorder psychopathology were statistically controlled. The findings suggest that exercise is excessive when its postponement is accompanied by intense guilt or when it is undertaken solely to influence weight or shape. Operational definitions of excessive exercise might usefully include reference to these terms. The findings may also be of benefit in informing the content of prevention programs, which address dysfunctional exercise behavior. Excessive exercise is unlikely to be associated with impairment in psychosocial functioning in the absence of eating disorder psychopathology. It may, however, be a useful indicator of such psychopathology.