[Background] Severe surgical insults are known to impair host immunity leading to infectious complications. We hypothesized that gut ischemia reperfusion (gut I/R) would have deleterious effects on hepatic mononuclear cells (MNCs). [Materials and Methods] Fifty-seven male ICR mice were randomized to the sham (n=13), I/R30 (n=12), I/R45 (n=17), and I/R60 (n=15) groups. The I/R30, I/R45, and I/R60 mice underwent 30, 45, and 60 minutes of superior mesenteric artery (SMA) occlusion, respectively. Forty-six mice (13 in sham, 11 in I/R30, 12 in I/R45 and 10 in I/R60) survived until postoperative day 2 (POD2). On POD2 the surviving mice were killed and hepatic MNCs were isolated, counted and analyzed for determination of phenotypes (Kupffer, T, B, NK cells) and TLR4 and CD14 expressions using flowcytometry. Plasma cytokines (IL-12p70, TNF-α, IFN-γ , IL-6, MCP-1 and IL-10) and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were also measured. [Results] There was a significant negative correlation between the ischemic period and hepatic MNC numbers (p=0.01, r=-0.375). The I/R60 group showed significantly smaller hepatic MNC number than the sham and I/R30 groups. With regard to the percentages of each phenotype, CD14 and TLR4 expressions, plasma cytokines, or ALT and AST levels, no significant differences were observed among the 4 groups. [Conclusions] Severe gut I/R reduces hepatic MNC number. Because hepatic MNCs play an important role in the elimination of pathogens and toxins in portal blood flow, we should be aware of the possibility of impaired hepatic immunity after severe gut I/R.