Microsatellites represent codominant molecular genetic markers, which are ubiquitously distributed within genomes. Due to their high level of polymorphism, relatively small size and rapid detection protocols, these markers are widely used in a variety of fundamental and applied fields of life and medical sciences. In the field of aquaculture, microsatellites represent workhorse markers, which are useful for the characterization of genetic stocks, broodstock selection, constructing dense linkage maps, mapping economically important quantitative traits, identifying genes responsible for these traits and application to marker-assisted breeding programmes. In this review, genomic distribution, function, evolution and practical applications of microsatellites are considered, with special emphasis on fish genetics and aquaculture. (c) 2005 Elsevier B.V. All rights reserved.