Monoclonal antibody-based treatment of cancer has been established as one of the most successful therapeutic strategies for both hematologic malignancies and solid tumors in the last 20 years. The initial combining of serological techniques for cancer cell surface antigen discovery with hybridoma technology led to a series of landmark clinical trials that paved the way for new generation antibodies and subsequent clinical success. Optimization of anti-tumor immune responses through Fc modifications has also made a major contribution to clinical efficacy. The modulation of immune system interplay with tumor cells through targeting of T cell receptors has emerged as a powerful new therapeutic strategy for tumor therapy and to enhance cancer vaccine efficacy. This commentary will provide an overview of the history of antibody identification of tumor surface antigens, antigenic targets suitable for antibody-based therapy, antibody mechanisms of action, and recent successes of antibodies in the clinic.