Review contains new data on protein fluoroimmunoassay (FIA), which combines advantages of RIA and EIA. Basic approaches to antibody production, principles of homogeneous and heterogeneous FIA as well as of time-resolved FIA properties of 28 fluorescent labels presenting various classes of organic compounds (of which most prospective are aminoquinolone, cyanocoumarines, chlorophylls, phycobiliproteins, metallorganic compounds) are described. Some examples of FIA application for quantitative evaluation of proteins in biological samples, properties of some FIA kits, and specifications of 6 fluorimeters developed for FIA are given. The nearest perspectives of FIA development and application in medical and biological research are considered.