BACKGROUND AND AIM: To in-vestigate the effects of systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndromes (MODS) on human peripheral blood endothelial progenitor cells. PATIENTS AND METHODS: Twenty patients admitted to Changhai Hospital, Second Military Medical University, from February, 2011 to November, 2011 were recruited consecutively. The serum samples were collected from the twenty patients who were divided into four groups as following: normal group, post-traumatic group without SIRS, post-traumatic group with SIRS, and post-traumatic group with MODS. Endothelial progenitor cells (EPCs) were isolated from peripheral blood of healthy subjects by using density gradient centrifugation and the effect of the serum on EPCs was detected after stimulating by the serum samples for 0, 6, 12, 24, and 36 h. RESULTS: Compared with the normal group, the proliferation of EPCs was significantly increased in a time-independent manner in the other three groups, especially in the SIRS serum treated group. The expression of pro-inflammation cytokines was increased in the other three groups compared with the normal group, but the expression of IL-10 in the normal group was higher than the other groups. CONCLUSIONS: Oxidative stress balance was also broken as the disease progressed. Serum from patients with sepsis could influence proliferation and the inflammation and oxidative stress states of EPCs.