This document provides an introduction to routine health information systems (RHIS). It defines RHIS as ongoing data collection of health status, interventions, and resources for decision-making. RHIS includes facility-based service statistics, epidemiological and surveillance data, community-based health information, and health administration data. The document outlines the components and standards of a national health information system according to the Health Metrics Network framework. It also describes the three levels of management that RHIS supports - beneficiary, health facility, and system management - and the importance of crafting useful indicators to monitor health services and systems.