Abstarct: The purpose of present study was to investigate the relationship between perfectionism and aggression among athlete students of Mazandaran province.The method of this study was descxriptive-correlation. So, 333 students athlete selected by random cluster sampling and completed demographics, sport multidimensional perfectionism of Gotwals & Dunn (2009) and athletic aggression of Bredemeier (1975) questionnaires. The validity of questionnaires was confirmed by constructive comments of sport management professors, coaches and athletes and their reliability determined by cronbach alpha coefficient of 0.89 and 0.83 respectively. The data were analyzed using descxriptive and inferential statistics Kolmogorov-Smirnove test, pearson correlation coefficient, ANOVA and independent t-test α≤0.05 significant level. The result showed negative significant correlation between Adaptive perfectionism and aggression of athlete students (p= 0.010, r= -0.142) and positive significant correlation between Maladaptive perfectionism and aggression of athlete students (p= 0.001, r= 0.449). Also, aggression of boy students in comparison to girl' students was more and There was no significant difference among aggression of athlete students in different fields. According to research result, Overall, perfectionism should not be considered as a negative predictor for aggression, because is reduces adaptive perfectionism to aggression. So, instead, attention should to both adaptive and maladaptive perfectionism dimension.