Technical Abstract: Streptococcus iniae and S. agalactiae are important emergent pathogens that affect many fish species worldwide, especially in warm-water regions. In marine and freshwater systems, these Gram-positive bacteria cause significant economic losses, estimated at hundreds of millions of dollars annually. Infection results in septicemia and neurotropic disease, with cumulative percent mortality between 30 to 50%. Streptococcal disease is very difficult to control because these pathogens are resistant or become resistant to most chemicals and drugs. The aim of this paper is to review current information on fish streptococcosis including aspects of epidemiology, diagnosis, pathogenesis, and prevention, treatment and control measures in farmed tilapia.