The present experimental study has focused on the immunomodulatory activities of purified microcin of local clinical isolate K. pneumoniaeon the immune system of albino mice. Twenty male albino mice aged 8–12 weeks and weight 26–30 gwere divided into four groups, three groups were treated with purified microcin at concentrations of1, 5, 10μg/mouse- IM, respectively for 12 days, the fourth is control group which was received normal saline, on day 4 and 8 of program, the four groups sensitized with 10% sheep red blood cells SRBCs intraperitoneally. The effect of purified microcin on the body weight of mice were studied on day 1 and 12 of treatment. After treatment of the groups, assays for evaluation of immunomodulation effects of the purified microcin were applied including: Arthus and delayed type hypersensitivity reactions, serum antibody titer, and levels of both TNF-alpha and IL-10 cytokines. Results of this study exhibited that the purified microcin have immunostimulatory activities on the murine immune system at concentration of 5 μg/ mouse. This effect reflected by improving the growth of mice, function of macrophages and lymphocytes, this reflected by increased the body weight, Arthus and DTH reactions, and antibody responses that controlled by the soluble mediators of the immune system include TNF-α and IL-10.