OBJECTIVE: To determine the effect of immunoglobulin (Ig)M-enriched Ig therapy on mortality rate and renal function in sepsis-induced multiple organ dysfunction syndrome (MODS), using the Acute Physiology and Chronic Health Evaluation II (APACHE II) score. METHODS: Retrospective study of patients with sepsis-induced MODS treated with standard antibiotic plus supportive therapy (control group) or IgM-enriched Ig therapy adjuvant to control group therapy (IVIg group). Total length of stay in the intensive care unit (ICU), overall mortality rate and 28-day case fatality rate (CFR), as well as APACHE II scores and renal function parameters at day 1 and day 4 of therapy, were recorded. RESULTS: A total of 118 patients were included (control group, n = 62; IVIg group, n = 56). In both groups, day 4 APACHE II scores decreased significantly compared with day 1 scores; the effect of treatment on renal function was minimal. Length of ICU stay, overall mortality rate and 28-day CFR were significantly lower in the IVIg group compared with the control group. CONCLUSIONS: Adding IgM-enriched Ig therapy to standard therapy for MODS improved general clinical conditions and significantly reduced APACHE II scores, overall mortality rate and 28-day CFR, although effects on renal function were minimal.