This protocol outlines fixation of blood and isolation of peripheral blood mononuclear cells (PBMCs) and leukocytes from the fixed blood for use with the Chromium Fixed RNA Profiling workflow. Storage recommendations for the PBMCs isolated from fixed blood and post-storage processing conditions are also provided. An overview of data derived from fixed PBMCs and leukocytes used with the Chromium Fixed Profiling workflow is also shown.