Disclosed herein are isolated human monoclonal antibodies, and functional fragments thereof, that specifically bind HMW-MAA. Nucleic acids encoding these antibodies, expression vectors including these nucleic acid molecules, and isolated host cells that express the nucleic acid molecules are also disclosed. The antibodies can be used to detect HMW-MAA in a sample. Methods of diagnosing cancer, or confirming a diagnosis of cancer, are disclosed herein that utilize these antibodies. Methods of treating a subject with cancer are also disclosed.