An evaluation of the physiological, biochemical and psychological results obtained by various investigators on participants in competitive marathons is provided. The historical background of the studies on marathon runners suggests that much of the early information has been forgotten and has resulted in repetitive studies providing no additional insight into the physiological problems of these runners. However, the basic information obtained since the first scientific studies of participants in the 1899 marathon race has provided interesting and valuable information. The value of this older basic information to present and future investigators is emphasized. Suggestions for additional research based on results from both the earliest and the latest studies of marathon runners are made. Increasing participation in marathon races by individuals of both sexes, by individuals with various kinds of pathology as well as individuals of varying levels of physical competence suggests the value and need for research on these individuals before, during and after their involvement in such a strenuous and physiologically demanding physical task.