Actinomyces are a rare cause of the intra-abdominal infection that results in chronic suppurative and infectious granulomatous disease. The liver is involved in 15% of cases with abdominal infection and comprises 5% of all cases. Major risk factors include previous surgery, abdominal trauma, gastrointestinal foreign body, gut lesions, and immunosuppression. Due to the insidious course of the disease, symptoms arise several months after onset of the disease. The diagnosis of liver actinomycosis relies on clinical manifestations and imaging findings. Thus, it is often misdiagnosed as a primary liver cancer or metastatic tumor. Here we describe a case of isolated hepatic actinomycosis that mimicked a hepatocellular carcinoma with pretreatment and posttreatment magnetic resonance imaging findings. The patient was cured with long-term antibiotherapy.