Bioluminescence is a light production phenomena performed by means of chemical reactions or cellular secretion existing in the cells of living organisms or in the cells and organs of the symbiotic organisms which live together with them. In this process, at least two chemicals, luciferin and luciferase, are required. Bioluminescence can be seen in a wide range of groups of aquatic organisms such as phytoplankton, zooplankton, annelids, molluscs, ctenophores, shrimps and fishes. Bioluminescence in aquatic organisms, just like in terrestrial biolumineseent organisms, provides hiding and protection, attraction of prey or communication. The most common example of bioluminescence is light production by Noctiluca miliaris called as "phosphorescence in the sea". Because it is thought that light-producing organisms (bioluminescent) may be used or cultured for many aims in the future, formation of bioluminescence, its usage by aquatic organisms and its effects will be tried to explain in this review.