In this paper, an active disturbance rejection control (ADRC) toolbox for MAT-LAB/Simulink is introduced. Although ADRC has already been established as a powerful robust control framework with successful industrial implementations and strong theoretical foundations, a comprehensive tool for computer-aided design of ADRC has not been developed until now. The proposed ADRC Toolbox is a response to a growing need of both scientific community and control industry looking for a straightforward software utilization of the ADRC methodology. Its main purpose is to fill the gap between current theories and applications of ADRC and to provide an easy-to-use solution to users in various control fields wanting to employ the ADRC scheme in their applications. The ADRC Toolbox contains a single, general-purpose, drag-and-drop function block allowing to synthesize a predefined ADRC-based strategy with minimal design effort. Its efficacy is validated here in both simulations and hardware experiments, conducted using a variety of problems known from motion, process, and power control areas. The proposed ADRC Toolbox is an open-source project 1 .