This study investigates the physical characteristics, body composition, cardiovascular and pulmonary functions, and aerobic capabilities of male and female long distance runners. Eleven runners volunteered to take tests to determine background information, body fat, oxygen uptake, and running time and pace. Conclusions made from this study include: (1) Male and female runners are slight in build with little body fat and possessing large lung volumes; (2) Male marathon runners are taller, heavier, and have less relative body fat than female runners; (3) Male and female runners did not differ in aerobic capabilities; (4) Experienced female runners are able to work at a high fraction of their aerobic capacity as are all male runners. Findings are illustrated in tabular form. (CJ)