CD19 is expressed on B- lineage cells and follicular dendritic cells and plays a key role in B cell malignancies and autoimmune diseases. Thus, it has been considered as potential target for several monoclonal antibodies (mAbs). For decades, chemotherapy has been known as one of the major antitumor therapies eradicating high proliferative tumor cells. But, anti- CD19 mAbs developed for treating CD19- positive lymphomas and autoimmune diseases would rank among the most novel area of research and development in the pharmaceutical industry. Moreover, several anti- CD19 mAbs are currently being tested in various clinical trials and this review provides an overview of the research accomplished so far.