The present invention provides a human monoclonal antibody, and antigen-binding portions thereof, capable of binding to human granulocyte-macrophage colony stimulating factor (hGM-CSF) and neutralizing the bioactivity of the hGM-CSF, wherein the anti-hGM-CSF monoclonal antibody has a light chain (L chain) including an amino acid sequence SEQ ID NO:1 and a heavy chain (H chain) including an amino acid sequence SEQ ID NO: 2. Also provided are human monoclonal anti-hGM-CSF antibodies, and antigen-binding portions thereof, characterized by complementarity determining regions (CDRs) or H chain and L chain variable regions related to SEQ ID NO:1 and SEQ ID NO:2. Antibodies, and antigen-binding portions thereof, of the invention are useful in the treatment of diseases associated with overproduction of hGM-CSF, including allergic disease, graft rejection and graft-versus-host disease (GVHD), and autoimmune diseases.