The aim of this study was to investigate the mediator role of cognitive flexibility in the relation between five-factor personality traits and life satisfaction. The sample in present cross-sectional research consisted of 620 university students, 460 female and 157 male. Samples ranged in age between 18 and 32, with a mean age of 20.80 (SD=2.07). Participants filled out the Five-Factor Personality Inventory, the Cognitive Flexibility Inventory and the Satisfaction with Life Scale. The personality traits of extraversion, agreeableness, conscientiousness and neuroticism emerged as significant predictors of life satisfaction. Additionally, there were significant relationships among personality traits, cognitive flexibility and life satisfaction. The mediation results revealed that cognitive flexibility is a significant mediator in the relation between personality traits and life satisfaction. These results provide information regarding a possible through which cognitive flexibility with its own dynamics may improve the determination of hedonic gains affection satisfaction with life.