The present invention relates to antibodies and antigen-binding portions thereof that specifically bind to a M-CSF, preferably human M-CSF, and that function to inhibit a M-CSF. The invention also relates to human anti-M-CSF antibodies and antigen-binding portions thereof. The invention also relates to antibodies that are chimeric, bispecific, derivatized, single chain antibodies or portions of fusion proteins. The invention also relates to isolated heavy and light chain immunoglobulins derived from human anti-M-CSF antibodies and nucleic acid molecules encoding such immunoglobulins. The present invention also relates to methods of making human anti-M-CSF antibodies, compositions comprising these antibodies and methods of using the antibodies and compositions for diagnosis and treatment. The invention also provides gene therapy methods using nucleic acid molecules encoding the heavy and/or light immunoglobulin molecules that comprise the human anti-M-CSF antibodies. The invention also relates to transgenic animals and transgenic plants comprising nucleic acid molecules of the present invention.