Pulmonary arteriovenous malformations are caused by abnormal communications between pulmonary arteries and pulmonary veins, which are most commonly congenital in nature. Although these lesions are quite uncommon, they are an important part of the differential diagnosis of common pulmonary problems such as hypoxemia and pulmonary nodules. 1 We report the case of a middle aged lady with subacute onset of mild breathlessness and cough, who was found to be cyanotic, severely hypoxic and hypoxemic on investigation. Thorough workup revealed solitary large pulmonary arteriovenous malformation, without involvement of any other symptoms or family history. She underwent embolo-therapy and had relief of symptoms. This case underlines a rare cause of a very common symptom like dyspnoea, and reiterates the need for thorough investigation and workup.