Background & Aim Human platelet lysate (hPL) is increasingly popular as a xenogenic-free alternative to FBS for manufacturing cell products. UltraGRO™ series products are manufactured from pooled human platelets collected from healthy donors at FDA-licensed, AABB-accredited blood centers. Each donor has been interviewed, evaluated, and donations are tested using FDA-approved methods for infectious diseases screening. Despite the low risk associated with the qualified transfusable platelet units, transmission of infectious agents remains a consideration for human platelet-derived products. In recent European Pharmacopoeia (Ph. Eur.) 9th Edition 5.2.12, implementation of a pathogen reduction procedure in the manufacturing process is suggested. Gamma irradiation is one of the most widely employed methods for pathogen reduction and commercial gamma sterilization facilities are easily accessible. The whole system for irradiated FBS has been well established and applied in clinical trials. Nevertheless, many research articles have addressed the optimal conditions for utilizing gamma irradiation in human plasma and blood components. With these comprehensive references, we previously assessed the feasibility of using gamma irradiation to obtain pathogen-reduced hPL and reported low impacts on the potency for cell expansion. Methods, Results & Conclusion In this study, we validated the efficacy of gamma irradiation for virus inactivation. Four model viruses (BVDV, Reo3, HSV1, MMV) were chosen, per ICH/EMA guidelines, to represent a range of viruses with different genome, structure, size, and sensitivity to various chemical and physical agents. The virus spiked hPLs were gamma irradiated and the mean values of viral titers showed over 4 log10 reductions across all model viruses. The results demonstrated gamma irradiation is an effective viral reduction procedure for hPL. To assess the impacts of gamma irradiation on the long-term stability of hPL performance, we analyzed UltraGRO™ GI series up to one year after gamma irradiation. The results showed growth factors still retained comparable levels to the non-irradiated hPLs. Mesenchymal stromal cells (MSC) cultured with gamma-irradiated hPLs for more than three passages showed similar profiles as with the corresponding non-irradiated hPLs in respect of growth rate, morphology, immunophenotype, trilineage differentiation potency, and immunosuppressive properties. Human platelet lysate (hPL) is increasingly popular as a xenogenic-free alternative to FBS for manufacturing cell products. UltraGRO™ series products are manufactured from pooled human platelets collected from healthy donors at FDA-licensed, AABB-accredited blood centers. Each donor has been interviewed, evaluated, and donations are tested using FDA-approved methods for infectious diseases screening. Despite the low risk associated with the qualified transfusable platelet units, transmission of infectious agents remains a consideration for human platelet-derived products. In recent European Pharmacopoeia (Ph. Eur.) 9th Edition 5.2.12, implementation of a pathogen reduction procedure in the manufacturing process is suggested. Gamma irradiation is one of the most widely employed methods for pathogen reduction and commercial gamma sterilization facilities are easily accessible. The whole system for irradiated FBS has been well established and applied in clinical trials. Nevertheless, many research articles have addressed the optimal conditions for utilizing gamma irradiation in human plasma and blood components. With these comprehensive references, we previously assessed the feasibility of using gamma irradiation to obtain pathogen-reduced hPL and reported low impacts on the potency for cell expansion. In this study, we validated the efficacy of gamma irradiation for virus inactivation. Four model viruses (BVDV, Reo3, HSV1, MMV) were chosen, per ICH/EMA guidelines, to represent a range of viruses with different genome, structure, size, and sensitivity to various chemical and physical agents. The virus spiked hPLs were gamma irradiated and the mean values of viral titers showed over 4 log10 reductions across all model viruses. The results demonstrated gamma irradiation is an effective viral reduction procedure for hPL.