Light chain deposition disease (LCDD) is a rare, plasma cell proliferative disorder characterized by mainly abnormal light chain deposition in various organs. Hepatitis C virus (HCV) is a hepatotrophic and lymphotrophic virus and significantly related to B-cell proliferation. This is a case report of systemic LCDD involving liver, stomach, bone marrow, and probably kidney, in a patient with HCV-related hepatocellular carcinoma (HCC). A 62-year-old man with chronic HCV infection who presented with a small HCC in segment 8 of the liver and nephrotic syndrome showed kappa typed immunoglobulin light chain depositions in biopsy specimens of bone marrow, stomach, and non-tumorous liver parenchyma. After treatment of the HCC with transarterial chemoembolization, antiviral therapy for chronic hepatitis C was started. The patient showed early virologic response at 12 weeks of treatment; however, antiviral therapy was discontinued due to adverse effects and he was lost to follow-up. This is the first case of LCDD involving the liver and stomach in a patient with chronic HCV infection and HCC, which may represent LCDD as a rare HCV-associated B cell proliferative disease.