Exercise in appropriate quantity and of proper quality contributes significantly to the preserve our health. On the contrary, excessive exercise may be harmful to health. The term 'exercise addiction' has been gaining increasing recognition to describe the latter phenomenon. The exact definition of exercise addiction and its potential associations with other disorders is still under study, although according to the authors this phenomenon can be primarily described as a behavioral addiction. Accordingly, exercise addiction, among other behavioral and mental disorders, can be well describe within the obsessive-compulsive spectrum suggested by Hollander (1993). There are several tools used to assess exercise addiction. The authors here present the Hungarian version of the Exercise Dependence Scale (Hausenblas és Downs, 2002) and the Exercise Addiction Inventory (Terry, Szabo és Griffiths, 2004). Exercise addiction has many symptoms in common and also shows a high comorbidity with eating disorders and body image disorders. It may be more closely associated with certain sports but more data is needed to demonstrate this specificity with more certainty. Sel-evaluation problems seem to have a central role in the etiology from a psychological aspect. The relevance of neurohormonal mechanisms is less clear. The authors emphasize the importance of further research on exercise addiction. One important question to be answered is if this disorder is an independent entity to be classified as a distinct clinical disorder or is it rather a subgroup of another disorder.