Pulmonary arteriovenous malformations (PAVMs) are direct communications between pulmonary arteries and pulmonary veins, resulting in right-to-left shunts that may cause cyanosis, dyspnea, and digital clubbing. Neurological complications such as intrace rebral hemorrhage or brain abscess may result from cerebral thrombosis or emboli. In most cases, they remain unrecognized until the late te enage years. Here, we report a case of a 6-year-old boy who presented with perioral cyanosis, digital clubbing, and dyspnea on exertion. A plain chest X-ray showed a focal nodular opacity in the right lower lobe (RLL), and a diagnosis of a large PAVM in the RLL was confirmed by chest computed tomography. A right lower lobe ctomy was successfully performed without any complications. Although their incidence in children is low, PAVMs should be suspected as a possible cause of cyanosis and dyspnea of non-cardiac origin, and should be treated promptly to prevent further neurological complications.