The study examined the influence of leadership styles and change management on job performance of Health Information Management practitioners in tertiary hospitals in 
South-West, Nigeria. The study employed survey research design. A sample size of 239 Health Information Management Practitioners in Tertiary Hospitals in South-West, 
Nigeria was employed using proportionate sampling technique. Besides, a self-developed structured questionnaire was used to gather data for the study. Data analysis involves both descriptive and inferential statistics. Result revealed a high level of job performance of Health Information Management practitioners in tertiary hospitals in South-West, Nigeria. In addition, the study revealed that leadership style and change management had a combined influence on job performance of Health Information Management practitioners in selected tertiary hospitals in South West, Nigeria (Adj. R2=0.287, β = 0.348, (t= 238), F (2, 238) = 12.234, p<0.05). The study therefore concluded that most Health Information Management Practitioners in South West Nigeria were performing well on their job as specified by Health information management practice. Despite the negative factors of wrong leadership styles there still exist high job performance because of skillfull trainings and professionalism. However, many do not adhere to policy of Health information management practice in the study area.

Key words: Leadership styles, Change management, Job performance, Health Information Management Practitioners, Tertiary Hospitals, South -West, Nigeria.