There is a great current interest in developing target-specific radiopharmaceuticals for early detection of diseases and radiotherapy of cancers. This critical review will focus on the role of coordination chemistry in the development of target-specific radiopharmaceuticals. It will also discuss the recent development in technetium, copper, gallium, indium, yttrium and lanthanide chemistry, as well as analytical tools for quality control and characterization of radiolabeled small biomolecules (159 references).