BACKGROUND Gerbode defect is a defect that communicates the left ventricle (LV) to the right atrium (RA). Although it was originally identified as a congenital defect, it is becoming more common accepted that the lesion has either an iatrogenic or non-iatrogenic origin. In this article, the author presents an unusual diverticulated appearance of direct Gerbode defect in an adult patient without any prior history of cardiac pathology and the surgical technique used, hoping to increase awareness of similar cases. CASE REPORT A 46-year-old man presented with worsening shortness of breath and fatigue for 2 years. The patient's medical history was only significant for high blood pressure, with no previous cardiac abnormalities. No other metabolic syndrome was identified in this patient. There was no family history of congenital heart disease. Echocardiography showed a Gerbode defect with left-to-right shunt from LV to RA. The author found a diverticulated lesion around the area of the Gerbode defect intraoperatively, which raised a suspicion that the diverticulum may have initiated the Gerbode defect. CONCLUSIONS Congenital heart disease is currently one of the most common congenital diseases which require surgical intervention. The vast spectrum of severity in many congenital heart diseases makes the diagnosis and early recognition challenging, so many patients live with the condition undiagnosed until adulthood. Any abnormality which causes left-to-right shunting must be identified as early as possible to prevent further complications such as congestive heart failure.