: Health care information systems are aimed at facilitating the smooth running and interoperability of the health care delivery processes to ensure efficiency and effectiveness; however, the complexity, heterogeneity and diversity of the health care sector especially in Kenya poses serious challenges especially in relation to integration of the systems. There is a large disconnect between the public and private health care delivery systems characterized by fragmentation of services, locally within hospitals (among primary, secondary and tertiary health care settings) and across different health care centers. This research is aimed at examining the adoption of integrated healthcare information system in Nairobi County; Kenyatta National Hospital represents the public sector and The Mater Hospital the private sector. A sample size of 100 users on information system from the two hospitals picked from the primary secondary and tertiary levels were selected and questionnaires administered to them. Data was analyzed through descriptive statistics with the aid of SPSS. The results of the study indicated that there was a huge disparity between healthcare information system adoption in the public and private sectors with the private sector’s adoption being at an advanced stage. The major barriers to adoption including social political barriers, financial constraints and technical/technological barriers also presented.