Cases of inferior phrenic artery-to-pulmonary artery fistulas and those complicated by massive hemoptysis have been rarely reported. A 38-year-old man presented to our hospital with a chief complaint of coughing. Computed tomography (CT) revealed a nodule in the left lower lobe, and contrast-enhanced CT showed inflow of contrast medium into the nodule. CT angiography detected an aneurysm associated with a left inferior phrenic artery-to-left pulmonary artery fistula. Transcatheter arterial embolization (TAE) was performed to prevent hemoptysis. Hemoptysis did not occur during the 2-year follow-up. We report a rare case of asymptomatic aneurysm associated with a left inferior phrenic artery-to-left pulmonary artery fistula, which was successfully treated using TAE to prevent hemoptysis.