The diagnosis of pulmonary embolism is challenging particularly when patients present with vague and/or non-specific symptoms and signs. Misdiagnosis of pulmonary embolism can lead to death or severe morbidity. We reported a case of a 60-year-old woman presented with recurrent syncope who later was diagnosed as submassive pulmonary embolism. This case report highlights the importance of early diagnosis and management of pulmonary embolism to prevent life-threatening sequels. Pulmonary embolism should be considered as a differential diagnosis of patients presenting at an emergency department with syncope.