The development and optimization of an effective non-viral gene delivery method for genetic manipulation of primary human T cells is a major challenge in clinical immunotherapy researches. According to the low transfection efficiency of conventional methods in human primary T cells, there is an effort in order to increase the transfection rate in these cells. Protamine is an FDA-approved compound with a documented safety profile that enhances DNA condensation for gene delivery. In this study, the effect of protamine on the transfection efficiency of standard transfection reagents, TurboFect, and Lipofectamine 2000 was evaluated in order to transfect primary human T cells. Results demonstrated that protamine condenses DNA and increases the positive charge of DNA/Cargo complex efficiently without any cytotoxic effect on the primary human T cells. The results also revealed that the DNA/Protamine/Cargo complexes effectively transfect human primary T cells.