This review focuses on the development of monoclonal antibodies that have been or are being introduced in the treatment of both lymphoid and myeloid haematological malignancies in adults. After a general introduction on the principles of antibody selection for therapy, this review summarizes the results of the clinical trials that led to the approval of antibodies by the FDA (Food and Drug administration, USA) and/or the EMEA (European Medicines Agency), e.g. different anti-CD20, anti-CD52 and anti-CD33 antibodies. Furthermore, several antibodies that seem promising in phase I/II studies (like anti-CD22, anti-CD23, anti-CD4, anti-CD30, anti-CD80, anti-VEGF, anti HLA-DR and anti-TNF) are highlighted. The application of monoclonal antibodies has nowadays become indispensable in the treatment of lymphoma and leukaemia's and the number of new indications is still growing. Therefore, also some interesting phase III studies that are recruiting patients at this moment, and some new technical developments are discussed.