Disclosed herein are human monoclonal antibodies that specifically bind both IGF-I and IGF-II with picomolar affinity and potently inhibit the IGF-IR signal transduction function. These antibodies are active in both an IgG and a scFv format. Bispecific forms of these antibodies are also disclosed. Nucleic acids encoding these antibodies, vectors including these nucleic acids, and host cells transformed with these vectors are also disclosed herein. Also disclosed are pharmaceutical compositions including these antibodies. Methods are provided for treating a subject with cancer and for inhibiting phosphorylation of the insulin-like growth factor-I receptor. Methods are also provided for diagnosing cancer.
