Treatment of patients with unconjugated MAb such as rituximab (Rituxan) the anti-CD20 MAb or trastuzumab (Herceptin) the anti-Her2 MAb, have shown efficacy in clinical trials and have gained approval from the Food and Drug Administration (FDA) has a result. Likewise, an anti-CD33 MAb conjugated with the antibiotic calicheamicin (Mylotarg) has proven efficacious in the treatment of patients with acute myeloid leukemia and has also been approved by the FDA. This overview presents some of the monoclonal antibody (MAb)-guided strategies with a focus on some of the experiences reported for MAb evaluated in clinical trials.