Pulmonary thromboembolism (PTE) is one of the most common and dangerous complications in orthopedic surgery. We experienced a fatal PTE in a 29-year-old man who had a simple fibular shaft fracture and cast immobilization for about one month. Despite simple fibular shaft fracture in patient with low risk for venous thromboembolism (VTE), a terrible outcome occurred. During immobilization, thromboprophylaxis such as low molecular weight heparin should be always considered. We report a rare case of PTE after simple fibular shaft fracture.