Tilapia culture has a special history in Thailand. Nile tilapia (Oreochromis niloticus) was granted as “gift” by the former prince of Japan to the former king of Thailand in 1965. Perceiving the potential value of phenomenal self-recruitment as seen in the pond in Chitralada palace where they were maintained, the King gave 10,000 fingerlings to the Department of Fisheries (DoF) and asked to distribute to the farmers. The DoF distributed the fish to 15 inland fisheries research stations to distribute to the public. Tilapia was the focus of AIT’s research since early 1980s. AIT maintained the stock in hapas-in-pond, conducted series of research trials over a decade, developed practical techniques of fry production and grow-out. Low-cost grow-out technique in green water coupled with nursing of fry in hapas at early stage was transferred through Aqua Outreach program in Asia. Due to the promotional efforts of various organizations, Nile tilapia gained increasing interest among farmers. It became the most widely cultured fish in Thailand overtaking catfish in total production since 90s. However, wide adoption of tilapia farming was still hindered by unavailability of large quantity of quality fry which was realized by researchers at AIT and attempts were made to find a practical solution to this. A success of producing consistently high-quality mono-sex fry on a mass scale using hormonal sex-reversal helped improve consistency of marketable size and improved profitability and encouraged intensification of tilapia farming. The mono-sex production method consists of techniques of maintaining large number of broodfish in hapas, collection and artificial incubation of their eggs (Fig. 1), and a practical method of sex-reversal. This combination of techniques developed at AIT was successfully transferred to the private sector in addition to the public sector with contractual arrangements. As a result, now there are over 100 hatcheries of its kind in Thailand alone; some of them supply up to 10-20 million monosex fry per month. This technology has now spread around the globe starting from Fiji in the east Bangladesh, Brazil, Myanmar, Nepal, PR China, the Philippines, Vietnam, and others. This paper describes the approaches and strategies applied by AIT, and some success stories/impacts which should be useful for many others.