The data described in this article are related to “High levels of eukaryotic Initiation Factor 6 (eIF6) are required for immune system homeostasis and for steering the glycolytic flux of TCR-stimulated CD4 + T cells in both mice and humans” (Manfrini et al., in press) [1]. eIF6 is a translation initiation factor required for ribosomal biogenesis (Sanvito et al., 1999) [2] and for proper translational initiation (Gallo and Manfrini, 2015; Miluzio et al., 2016) [3,4] whose protein abundance requires tight regulation. Here we analyze by flow cytometry the effects of eIF6 depletion on proportions of specific innate and adaptive immune system subpopulations and on thymocyte maturation in mice.