Abstract: This paper presents the study concerning how the personality traits influence usage of health informatics systems in Kenya, especially Nyanza Region. The objectives of this study were, first to examine the personality traits exhibited by the health professionals in Level 5 hospitals in Nyanza, Kenya. Second to analyze the health workers usage of health informatics and third was to examine how the personality traits influenced usage of health informatics in Nyanza, Kenya. The questionnaire survey technique was purposefully adopted for this study to collect the data randomly from a sample population of 163 health workers in Level 5 Hospitals in Nyanza, Kenya.