Light chain disease is a rare type of plasma cell neoplasm. Its clinical feature is similar to that of other myeloma but its survival time is shorter than others and it secretes different type of M-conponent. The department of Clinical Pathology, Severance hospital, has run immunoelectrophoretic studies for the last 2 years and detected a case of Light chain disease recently. A relative hypogammaglobulinemia was found on the ordinary gerum electrophoresis. On the immunoelectrophoretic study, an antigen excess with deformation on the medical protion of IgG line on polyvalent antiserum and a deformation with partial identity on Kappa antiserum was noticed but the other fractions are of normal pattern. This is to report the case with clinical history and laboratory studies. A brief review of current literature is added.