A fully-human monoclonal antibody directed against human vascular endothelial growth factor receptor 3 (VEGFR-3; Flt-4) with antiangiogenic activity. Anti-VEGFR-3 monoclonal antibody IMC-3C5 specifically binds to and inhibits VEGFR-3, which may result in inhibition of tumor angiogenesis and a decrease in tumor nutrient supply. VEGFR-3 plays a critical role in the embryonic vascular system development but is restricted postnatally to endothelial cells of lymphatic vessels and found to be expressed in many solid and hematologic malignancies.