Streptococcosis is a serious bacterial disease responsible for significant economic losses in wild and farmed fishes It is the second disease threat to O. niloticus. Several species of Streptococcus have been reported worldwide as etiological agents of the disease. Also, other related bacterial species such as Lactococcus garvieae, Vagococcus salmoninarum, and Enterococcous faecalis with varied degrees of pathogenicity have been implicated in streptococcal infection. Streptococcosisis characterized by hemorrhagic septicemia, pop eye, nervous manifestation, abnormal swimming behavior, and high mortalities. Control of Streptococcosis is principally achieved by implementing some preventive measures and treatment with antibiotics and to a lesser extent vaccination. Probiotics and immunostimulants can be used to enhance host immunity against the infection with some success. The majority of streptococcal species exhibited multiple antimicrobial resistance; thus, vaccination appears to be the most effective method of controlling in aquaculture. This present review summarizes some aspects of Streptococcosis such as history, epidemiology, diagnosis, and possible control measures in cultured O. niloticus and its status in Egypt