AbstractMagnetic Resonance Companion (MestRe‐C) is a software package that offers state‐of‐the‐art facilities for data processing, visualization, and analysis of high‐resolution nuclear magnetic resonance (NMR) data, combined with a robust, user‐friendly graphical interface that fully exploits the power and flexibility of the Windows platform. The program provides a variety of conversion facilities for most NMR spectrometer formats and includes all the conventional processing, displaying, and plotting capabilities of an NMR program, as well as more advanced processing techniques. A brief review of the basic concepts of NMR data processing is included also. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part A 19A: 80–96, 2003.