The purpose of this study is to evaluate the effectiveness of a block of ten P.E. lessons on teenagers (n°= 46 experimental group, EG; and n°= 27 control group, CG) when playing mini-rugby and fights. Students completed the Aggression Questionnaire (AQ) before and after this period. The 29 items focused on the four aspects of aggression: physical (PA, 9 items), verbal (VA, 5), anger (A, 7) and hostility (H, 8). For each question, they wrote from 1 (false) to 5 (true). Regarding the Δ% an incremental % of EG on CG was found: 13.37% VA, 7.51% A, 5.15% H and 8.36% TOT AQ; the only value that decreased was PA (-1.76%). The Δ% average, of the four subscales, is positively equal to 10.63% for EG, while CG showed a -0.83%. With regards to the total score, the values obtained are the following: PA (EG) -1.43/PA (CG) +2.11 (average +0.34), VA (EG) -2.37/VA (CG) -0.63 (-1.5), A (EG) -2.06/A (CG) -1.67 (-1.87), H (EG) -0.25/H (CG) +0.37 (+0.06) and TOT AQ (EG) -4.82/TOT AQ (CG) -1.18 (-3). The test showed that the aggression improved by 10% in EG.