Acute myocardial infarction and pulmonary embolism can have life-threatening consequences such as congestive heart and respiratory failure, respectively. Cancer patients are at great risk of both acute myocardial infarction and pulmonary embolism complications because the malignancy sparks the patient's blood hypercoagulable state. Nevertheless, the literature currently offers only a few reports on acute myocardial infarction associated with pulmonary embolism, and two of them occurred in the same cancer patient. Here, we present a case of a 60-year-old woman who had been diagnosed with lung cancer. She was admitted to the emergency department twice. She was diagnosed with acute myocardial infarction at her first admission, when she experienced sudden-onset chest pain. Electrocardiography showed ST-segment elevation in leads V1-V3 with inverted T wave and pathological Q wave, suggesting an acute myocardial infarction. Coronary angiography revealed a thrombus in the left anterior descending coronary artery, and thrombus aspiration was performed. After 1 month, she had an attack of pulmonary embolism with syncope upon the second admission. A computed tomographic pulmonary angiography showed branches of right and left pulmonary embolism. Anticoagulation and antiplatelet measures were taken. In this article, we discuss the relationship between cancer and thrombosis with a special focus on the conservative management strategy regarding anticoagulant and antiplatelet therapy in our case.