SummaryFulminant pneumococcal infection is a fatal pneumococcal infection that tends to occur in immunocompromised hosts, such as patients who are asplenic or on immunosuppressant therapy. We experienced a case of a 73-year-old Japanese man with a medical history of coronary stent implantation and catheter ablation for atrial flutter who presented with dyspnoea at rest. The patient was diagnosed with streptococcal pneumonia based on a urine antigen test and CT. Despite the use of effective antibiotics and systemic therapies, his clinical course was rapidly progressive and he died 18 h after admission. This case of fulminant pneumococcal infection is reported along with the autopsy findings.