The Immunological Proteome Resource (ImmPRes; http://immpres.co.uk/) is an open access public resource integrating proteomic data generated by large-scale mass-spectrometry analysis of murine hematopoietic populations. The initial focus is T lymphocytes and how their proteomes are shaped by immune activation, environment, and intracellular signalling pathways with an aim to expand it to B cells and innate immune cells. It is a multidisciplinary effort between immunology and mass spectrometry-based labs with the objective to help define an in-depth high-quality map of immune cell proteomes. Maintaining data reproducibility and integrity are a priority within the resource, thus there is an in-depth protocols section explaining in detail the sample processing and the mass spectrometry-based analysis. ImmPRes provides open access to proteomic datasets covering a wide range of murine leukocyte populations with analysis of copy numbers per cell of > 10,000 proteins, enabling new understanding of lymphocyte phenotypes. All data is accessible via a simple graphical interface that supports easy interrogation of the data and options to download data summaries and raw data files.