With increasing involvement of young children in competitive sports there have been many studies on the cardiorespiratory response of children to endurance training. There were many methodological and design restrictions which limited the depth of studies in this area and made comparisons across studies difficult. Sufficient experimental progress has been made to draw the following conclusions. Trained children exhibit higher VO2max values than do untrained children. These differences are present irrespective of the ages of the children but are more pronounced in many cases in older children. Exercise programmes which are of sufficient intensity, frequency and duration lead to improvements in cardiorespiratory capacity. The minimum and optimum levels for intensity, frequency and duration have not yet been identified. The majority of the current literature assumes that children respond to endurance training in a manner similar to that of adults. This point needs further verification. The age or maturity level during which exercise training exerts its greatest effect on the cardiorespiratory system has not been clearly identified.