Persistent truncus arteriosus (PTA) is a rare conotruncal defect, defined as a single arterial vessel arising from the heart, which gives origin to the systemic, pulmonary and coronary circulations. It has an extremely poor prognosis and carries a high mortality rate during the early years of life unless surgically repaired. A few known cases have been reported of patients reaching maturity, and exceptionally, patients suffering from this disease having lived into the fourth decade. The purpose of this report was to present a new case of PTA type 1, diagnosed by echocardiography and MRI, in a 41-year-old woman, with the peculiarity of long survival into adult life. She had also experienced a full-term pregnancy and delivery of a normal infant three years prior to her diagnosis. Pulmonary vascular disease made her condition inoperable but she was doing well with medical management after a follow up of 15 months. Based on this work, we concluded that pulmonary arterial hypertension is deleterious for life in some cardiovascular diseases, but in others, allows survival, as occurred in these patients with PTA. The patient's clinical course and anatomical findings are reported, along with factors that may have contributed to her longevity.