Aim: The aim of this survey is to examine the effects of physical training on erythrocyte membrane fatty acids percentages as well as to analyze cellular adaptations in young sportsmen.Methods: Forty-four male volunteers participated: a group of 22 Trained players (TG) (age: 17.86 ± 0.36 years; weight: 69.86 ± 4.53 Kg; height: 1.78 ± 0.54 m), with a regular football training plan of 10 hours/week, and a group of 22 Untrained participants (UG) (age: 18.23 ± 0.49 years; weight: 72.10 ± 8.56 Kg; height: 1.68 ± 0.39 m). Gas chromatograph HP-5890 Series II was used to determine fatty acids concentrations. Results:Higher levels were obtained in the TG group in C12:0 (0.31 ± 0.35 vs. 0.03 ± 0.04%, P < 0.001) and in n-6/n-3 index (8.74 ± 5.20 vs. 4.29 ± 1.09, P < 0.001), and lower values in C22:6 (3.00 ± 3.51 vs. 5.08 ± 1.44%, P < 0.01) in comparison with the UT group. Moreover, a correlation of these parameters and the Lipid Peroxidation index with training degree were observed. Conclusion:10 hours/week aerobic-anaerobic football training program produces C12:0, n-6/n-3 index, C22:6 modifications in erythrocyte membrane.