Objectives This study examined the results of the restandardization of the Korean Personality Assessment Inventory (PAI). The Korean PAI was first standardized in 2001 and then restandardized in 2019 to establish new normative data. On the other hand, differences may exist in the results of the restandardized version considering the time interval, which may include cultural and social differences. Thus, differences between the results of the Korean PAI administered in 2001 and 2019 must be examined to confirm its new normative data followed by restandardization. Methods Data from 2212 adults who administered the original Korean PAI in 2001 and 1263 adults who administered the Korean PAI in 2019 were collected. The study compared the reliability and mean scores. In addition, the mean scores of the Korean PAI administered in 2019 were converted to T-scores adapted to the normative data of 2001. The collected data was analyzed using a t-test and comparing the T-scores. Results The internal consistency reliability showed a similar pattern in both versions, but the differences among the mean scores and T-scores appeared to be significant. Conclusion The significant differences between the scores of the Korean PAI administered in 2001 and 2019 reflect the result of the restandardization. Therefore, the restandardized version of the Korean PAI may bring more precise information that can be adapted to the contemporary era.