We encountered a case of arteriovenous malformation (AVM) of the gallbladder in a patient with hepatocellular carcinoma (HCC). Contrast-enhanced computed tomography (CT) showed serpentine vessels around and within the gallbladder wall. Angiography showed dilated and tortuous cystic arteries, a racemose vascular network, and early-filling cystic veins. Transcatheter arterial embolization of two cystic arteries feeding the AVM was performed with platinum microcoils prior to transcatheter arterial chemoembolization for HCC to prevent embolic particles from flowing into these arteries. Follow-up contrast-enhanced CT showed blood flow in the gallbladder AVM, which appeared to be fed by the arterial collaterals.