Several alpha emitting isotopes have been proposed for radioimmunotherapy. To produce these nuclides reliably and in quantities needed, unique manufacturing approaches will be required. This paper describes the approaches that are being developed for the manufacture of225Actinium (225Ac) that decays to213Bismuth (213Bi) and the commercial manufacturing approaches. Oak Ridge National Laboratory (ORNL) currently supplies the actinium used for research and medical use. Today the ORNL233U stockpiles only provide sufficient material for research quantities of213Bi. At the Institute for Transuranium Elements (ITU), in Karlsruhe, researchers have also developed a method of irradiating radium‐226 with protons in a cyclotron to produce actinium‐ 225 through the reaction226Ra (p, 2n)225Ac. Researchers from the Missouri University (MU), the Missouri University Research Reactor (MURR), MedActinium, Inc. and Los Alamos National Laboratory (LANL) are working on a collaborative effort to benchmark and optimize the production of213Bi via neutron bombardment of226Ra. MedActinium, Inc., in collaboration with commercial and institutional investigators at PG Research Foundation (PGRF) and Memorial Sloan Kettering Cancer Center (MSKCC), is developing commercial approaches to manufacturing these unique radioimmunotherapeutic drugs. © 2003 American Institute of Physics