The aim of the present study was to test the cross-cultural validity of the five-factor nature of personality. For this aim, an indigenous, psychometrically strong instrument measuring the basic personality dimensions within Turkish culture and language was developed through three consecutive studies. The first study aimed to reveal the adjectives that have been most frequently used to define people in the Turkish culture. In the second study, factor analysis of these personality characteristics revealed big five personality factors, along with the sixth factor, which had been called as the Negative Valence factor. The adjectives that most strongly represented and differentiated each factor constituted 45-item "Basic Personality Traits Inventory". Finally, in the third study, psychometric characteristics of the Basic Personality Traits Inventory were examined. Factor structure and psychometric properties of this instrument confirmed that five-factor nature of personality may not hold true in every culture.