The Personality Assessment Inventory (PAI) has been translated into different languages (e.g., Spanish, German, and Greek) and several authors investigated psychometric properties, internal structure, and the convergent validity of translated versions of the PAI. Recently, an Italian version of the test has been published, but its psychometric properties has never been explored. The aims of the present study were: (a) to examine the hypothesized subscale structure of scales that have subscales, (b) to evaluate the internal structure of the 22 PAI full scales, and (c) to report on the convergent validity of the PAI scales with the Millon Clinical Multiaxial Inventory-III (MCMI-III) scales. The sample consisted of 1,538 participants recruited from all over Italy. Our findings provided support to the cross-cultural applicability of the PAI and contributed to enhance confidence in the validity and utility of the PAI.