The aim of this study was to Survey the relationship between big five factor, happiness and sport achievement in Iranian athletes. In order to 72 athletics (Consist of 21 national tem athletes, 25 professional athletes and 26 non- professional athletes) who were selected using a access sampling, were assessed using Big Five Factor Inventory (FFI) (Costa & McCrae , 1992), Happiness Scale (Argyle , 2001) and Sport Achievement (Duda, & Nichols , 1992). The results were analyzed by Pearson correlation quotient, regression and, ANOVA test. Results showed that in compare with non- professional athletes the amount of neuroticism was significantly less that national tem and professional athletics (P<1%), The amount of extraversion, happiness and openness was significantly further that national tem athletics in compare with other groups (P<1%), also results showed that the amount of agreeableness and conscientiousness was significantly further that national tem athletes in compare with other groups (P<1%). Results showed that in national tem athletics and professional athletes were negative and significant correlation between sport achievement with neuroticism (P<5%), also positive and significant correlation between extraversion, agreeableness, conscientiousness, openness and happiness with sport achievement (P<1%). The analyses data by regression showed that in national tem athletes and professional athletics, sport achievement predicted by agreeableness and conscientiousness. Most research in the field of these variables can represent brighter data.
