Pulmonary arteriovenous malformations (PAVM) are rare pulmonary vascular anomalies. Although most patients are asymptomatic, right to left shunt produced by PAVM, could result in easy access of septic or non-septic emboli to systemic circulation, end to serious central nervous system (CNS) complication. Here we report a case of brain abscess in a young man. Its source was initially unknown but multiple arteriovenous malformations were detected incidentally in his thoracic CT, which was performed for ruling out embolism. Although the cases of brain abscesses associated with PAVM are very rare, the brain abscess could be an initial clinical manifestation in asymptomatic PAVM as in the case presented in this report.