Isolated absence of a pulmonary artery is an exceptional cause of massive hemoptysis. We report a 35-year-old woman with agenesis of the left pulmonary artery who presented with exsanguinating hemoptysis that prompted angiography with the aim to embolize the bleeding vessels selectively. The procedure could not be completed because of the presence of an anterior spinal artery branching from the aberrant systemic-to-pulmonary circulation. The patient successfully underwent an emergent pneumonectomy.