The DESI Instrument Control System (ICS) is designed to perform all control and monitoring functions required to operate DESI. This includes all data acquisition and flow, connection to the Mayall Telescope Control System, monitoring infrastructure, maintenance of an operations database, guiding, coordinate transformations, subsystem coordination, and user interfaces. At the core of the ICS is the DESI Online System (DOS). This includes an application framework for the subsystems’ distinct software. DOS also contains all of the user interfaces, which display exposure sequences, real-time telemetry, and image previews. The Observation Control System (OCS), which orchestrates exposure sequences, controls the flow of data from one subsystem’s software to another using a sequence-oriented architecture. DESI will collect a large amount of metadata and telemetry information, which will be recorded in the operations database.