Individual users are known to differ in their tendency to adopt new technologies. Among the individual differences, Personal Innovativeness in IT (PIIT) has been shown to be a reliable predictor of users' beliefs about the ease of use and usefulness of new technologies. However, it is unclear what are the personality traits that make some users more innovative in IT than others. Personality traits are used in the psychology literature to explain human beliefs and behavior, and recently see a growing interest in the IS literature as an explanatory tool of user behavior. The present research investigates two personality traits established in the psychology literature, Resistance to Change (RTC) and Openness, as determinants of PIIT. A survey of 121 prospective users of a digital library system was conducted to test our hypotheses. The findings suggest that RTC and Openness are determinants of PIIT. Implications for research and practice are discussed.