Recently, extensive research has been done in the area of bio-oncology. Bio-oncology focuses on four targets in particular: angiogenesis, signal transduction, B-cell biology and apoptosis. Monoclonal antibodies (mAbs) are a novel technology that can offer a world of opportunity by interfering with these pathways. In the past decade, a number of antibody-based products have emerged for the treatment of patients with different types of cancer. To date, nine therapeutic mAbs have been approved by the FDA for the treatment of oncologic diseases. This review explores these mAbs and analyzes their mechanism of action, as well as side effects specific to each. It also focuses on the unique features and limitations of mAbs as a mode of therapy and looks at some of the possible future endeavors for this novel therapeutic class.