[en] The paper studies hormesis of low dose radiation (LDR) in the expression of cytokines in umbilical cord blood (UCB). 1h after irradiation of UCB with 5 cGy of ²²⁶Ra γ-rays, the levels of IL-2, IL-8 EPO and SOD-1 were determined by radioimmunoassay (RIA). Compared with the control (0 Gy), the levels of all the assayed cytokines in the irradiated samples were up-regulated, with significant differences for IL-2, IL-8 and SOD-1 (p<0.05) and very significant difference for EPO (p<0.01). LDR with ²²⁶Ra γ-rays could induce hormesis as to the expression of IL-2, IL-8, EPO and SOD-1 in UCB