Mass spectrometry (MS)-based proteomics is the most comprehensive approach for the quantitative profiling of proteins, their interactions and modifications. It is a challenging topic as a firm grasp requires expertise in biochemistry for sample preparation, analytical chemistry for instrumentation and computational biology for data analysis. In this short guide, we highlight the various components of a mass spectrometer, the sample preparation process for conversion of proteins into peptides, and quantification and analysis strategies. The advancing technology of MS-based proteomics now opens up opportunities in clinical applications and single-cell analysis. - doi.org/10.1042/BIO20200057 - 2020