Research on personality is important in the field of entrepreneurship. The objective of this paper is to present the development and initial validation of the Entrepreneurial Dispositions Personality Inventory (EDPI), a new instrument measuring the personality predictors of entrepreneurial behaviour. Three studies carried out on the Polish samples are reported in the paper. Study 1 aimed at testing the pilot version of the EDPI and determining its basic psychometric properties. The findings of this study allowed the pool of items to be reduced from an initial 131 items to 86 items. Study 2 aimed at verifying the convergent validity of the 14 subscales of the EDPI. Almost all of the subscales (with the exception of Authoritative Parenting) showed the expected pattern of correlations with similar concepts, as measured by independent tools. Study 3 aimed at testing the construct validity of the EDPI by comparing the EDPI scores of entrepreneurs and non-entrepreneurs. This study also confirmed the expected direction of differences between these groups for the majority of the subscales. In conclusion, the EDPI can be a useful tool for measuring entrepreneurial personality predispositions, particularly in a country where such tools are missing