This document provides an overview of health management information systems (HMIS). It discusses how HMIS can help improve health service management by transforming data into useful information. Effective HMIS require collecting appropriate data, analyzing it, and disseminating summaries to support decisions at all levels of health management, from individual patient care to national policymaking. While new technologies continue to evolve, many existing health information systems still collect irrelevant data and do not utilize information optimally. For HMIS to fulfill their potential, stakeholders must be engaged and systems designed with user needs in mind.