A 41-year-old man presented to the emergency room for evaluation of substernal chest pain, shortness of breath and generalized failure to thrive. Patient had history of hepatitis B and HIV. During recent evaluation of hepatic mass, patient was found to have hepatocellular carcinoma on biopsy. Patient had no history of cirrhosis of the liver in the past. On Echocardiogram patient was noted to have a large mass filling the right atrial cavity. CT scan of abdomen, pelvis and chest showed a diffusely enlarged heterogeneously enhancing liver consistent with large hepatoma, with portal venous and hepatic vein thrombosis. Tumor thrombus extended through the hepatic veins and upper inferior vena cava into the right atrium. There was 6 cm greatest diameter enhancing mass in the right atrium. Patient had primary hepatocellular carcinoma with extensive invasion into vascular structures. His prognosis was poor and patient opted for palliative care only. In conclusion, patients with co-infection of HIV and Hepatitis B are at risk of developing hepatocellular carcinoma with extension into the right atrium and physicians managing these patients should have high suspicion of right atrial involvement with tumor extension and low threshold to order a screening echocardiogram.