Overwhelming postsplenectomy infection (OPSI) is a life-threatening condition causing fulminant bacteremia in asplenic patients. Intravenous immunoglobulin (IVIG) therapy is theoretically effective for OPSI. Herein, we present a case of OPSI treated successfully with IVIG, along with results of a literature review. An asplenic 70-year-old male with acute ischemic stroke presented with rapid and fulminant septic shock from pneumococcus pneumonia and bacteremia. Resuscitation and antibiotics including IVIG therapy were instituted. The patient survived with favorable outcomes. We analyzed all case reports or case series of OPSI from 1971 through 2017. Cases with IVIG treatment showed a significantly higher survival rate than those without IVIG, even with multivariable regression analysis, suggesting IVIG as an independent predictive factor for survival. It suggests that IVIG is effective for OPSI and that it can be regarded as an adjunctive treatment option for OPSI.