The purpose of the present study was to produce and characterize a monoclonal antibody against human ${eta}_2$-adrenergic receptor. Male BALB/c mice were immunized with glutathione S-transferase (GST) fusion protein of the C-terminal portion of the human ${eta}_2$-adrenergic receptor which was expressed in E.Coli. The immunized splenocytes were fused with myeloma SP2/0-Agl4 cells. The resulting hybridomas were screened for the production of a monoclonal antibody which can recognize human ${eta}_2$-adrenergic receptor, and then subcloned by limiting dilution. The resulting monoclonal antibody was named as mAb$eta$CO2. The mono-clonal antibody $eta$CO2 was determined as IgM subtype and then purified by anti-mouse IgM-agarose affinity chromatography. The results of ELISA, Western blot, and immunocytochemistry showed that mAb$eta$CO2 recognized human ${eta}_2$-adrenergic receptor in the ${eta}_2$-adrenergic receptor-GST fusion protein and human spider-moid carcinoma cell line A431 with highly specific immunoreactivity, The monoclonal antibody $eta$CO2 may provide useful tools for the study of the $eta$-adrenergic receptor of human and other species including rats.