The question of ideal body weight historically is a subject of study that raises more questions than answers. However, there are more accurate methods available to determine the ideal body weight. Where among health care professionals, the best-known method for assessing body size is the body mass index. While weight is not the best indicator in the case of athletes due to increased bone and skeletal muscle. since the BMI is limited perfect measure to interpret the body fat confirmed by repeated analysis in the similar studies. Gregory L. Landry appointed that there are better measures to adapt the optimal ideal body weight to the specific .Where Michael M. Rothkopf, et al indicts It is important for the metabolic physician to know the ranges for BMI in terms of the weight category . The current study compared fat mass versus body mass index as a relationship connectivity contributes to the prediction of the aerobic capacity growth level to monitor the football player weight. Methods: Thus, Ideal body weight in terms Heath  are the weight associated with the lowest mortality rate estimated as  body form in terms performance sportive . based on the less mass body fat. Where Body weight is easily measured, but not always a good indicator of body composition changes that control should be included as part of a comprehensive weight management. based on aerobic fitness which is related to body weight as the soccer game is largely aerobic sport . this study was undertaken and aimed at the evaluation of the relationship between Body Fat VS body mass index composition contributing to a healthy aerobic fitness body weight program among 160 male soccer players their age category under 19 years. Based on the descriptive method using the cooper test as a physiological parameter to esteem VO2max, and weight-height to calculate the BMI and body fat as anthropometric measurements. Results: based on the results obtained and applied statistics the most important finding of our study concerns within: The body fat and Height as best predictors of the level VO2max. The body fat is best predictors of the adjusted healthy aerobic fitness body weight. Conclusions: the current study supports the hypothesis that BMI alone should not be used to determine an “ideal” body where the level of VO2max is the best predictor of the body composition, However, to develop equation more studies are needed to prove this hypothesis.