Technical Abstract: AAquaculture is one of the fastest growing sectors of agriculture globally. Production in freshwater and marine fisheries has plateaued, and the continued demand for seafood and need for affordable protein sources in third world countries will ensure growth of aquaculture in the future. Tilapia are the second most cultured fish worldwide behind the carps, and even though they are easily cultured in a wide variety of environments and are resistant to aquaculture stressors, significant losses to disease still occur under intensive culture. Traditionally, antibiotics and other chemicals have been used to treat disease outbreaks in cultured fish species. However, the scope of approved application for most antibiotics is very narrow or their use is banned outright in many countries and concern over development of antibiotic resistant pathogens will further limit use in the future. The focus instead has turned to finding safe and effective means of preventing infectious diseases in cultured finfish, including tilapia. In recent years, there has been considerable interest in the use of probiotic bacteria added to diets to increase immunity as well as improve growth performance in fish. Little probiotic research has been conducted in tilapias, but of the research that has been performed, most has taken place within the last five years. Due to its apparent effectiveness in improving health and growth in tilapia, research and interest in probiotics is likely to continue, which will hopefully fill existing research gaps.