Cytotoxic CD8 + T cells can effectively kill target cells by producing cytokines, chemokines and granzymes. Expression of these effector molecules is however highly divergent, and tools that identify and pre-select potent killer cells are lacking. Human CD8 + T cells can be divided into IFN-g and IL-2 producing cells. Unbiased transcriptomics and proteomics analysis on cytokineproducing fixed CD8 + T cells revealed that IL-2 + cells produce helper cytokines, and that IFN-g + cells produce cytotoxic molecules. IFN-g + T cells could be identified with the surface marker CD29 already prior to stimulation. CD29 also marked T cells with cytotoxic gene expression from different tissues in single-cell RNA-sequencing data. Notably, the cytotoxic features of CD29 + T cells were maintained during cell culture, suggesting a stable phenotype. Pre-selecting CD29expressing MART1 TCR-engineered T cells potentiated the killing of target cells. We therefore propose that CD29 expression can help evaluate and select for potent therapeutic T cell products.