This document provides an overview of health management information systems (HMIS). It defines HMIS as a system that provides timely and reliable health information to managers to help with decision making. The document outlines the sources and subtypes of data in an HMIS, including epidemiological surveillance, routine service reporting, and vital registration. It also discusses the flow of data from patients and health units to the overall health system. Key health indicators are explained, such as infant mortality, immunization coverage, and health resources. The document concludes with references on HMIS concepts and the Ethiopian national set of 131 HMIS indicators.