Objective: The aim of the study was to develop the Multidimensional Personality Inventory based on the Big Five Personality model and lexical trait approach and to examine its psychometric properties. Methods: The study consisted of two stages. A total of 1098 people, 503 men and 595 women, between the ages of 18 and 76 participated in the first stage of the study. A total of 1828 people, 1060 men and 768 women, between the ages of 18 and 60 participated in the second stage of the study. Along with the developed inventory, 100 and 35 items the Big Five Scales and the Adjective Based Personality Scale were administered to assess convergent validity. 1009 Of the participants answered four of the measuring instruments. Results: In the first stage factor, analysis explained 34.862% of the total variance; these five factors were named as: Extraversion, Agreeableness, Conscientiousness, Emotional Stability, and Openness to Experience. The construct of the inventory was created with 30 sub-dimensions under the factors and with the Social Desirability sub-dimension held outside of the five factors. Item selection process was conducted by item analysis, Item Response Theory and Explanatory Factor Analysis. In the second stage the construct o the inventory was tested by Confirmatory Factor Analysis, acceptable fit indices were obtained. Inventory showed internal-consistency reliabilities ranging from 0.907 to 0.963 for factors and from 0.784 to 0.923 for sub dimensions, for the convergent validity high correlation coefficients for the factors of 100 and 35 items Big Five Scales and Adjective Based Personality Scale were calculated. Discussion: The results show that the Multidimensional Personality Inventory needs other reliability and validity studies however, the Multidimensional Personality Inventory, carry basic psychometric properties for practical uses. [Anadolu Psikiyatri Derg 2018; 19(0.200): 5-13]