A 40-year-old healthy housewife died after joining a special summer camp for her diabetic daughter. The victim sat for 4h 40 min while traveling by car on the day before her death. Autopsy revealed she died from a pulmonary thromboembolism (PTE), whereby portions of a blood-clot that had been formed in the internal iliac veins detached and traveled to the lungs, blocking the pulmonary blood flow. The leg veins are the most common source of thromboembolism; PTE caused by thromboemboli from the internal iliac veins is rare. We discuss the mechanisms of the present victim's death, and the conditions and risk factors involved in PTE.