With the onset of Tilapia Lake Virus (TiLV) outbreaks in several Asian countries, WorldFish, in collaboration with Bangladesh’s Department of Fisheries, has developed a program to improve biosecurity in the tilapia industry throughout the country. As the first step, a training program has been designed and conducted to train a group of specialists called Master Trainers on improving tilapia hatchery biosecurity. This manual is a result of that program. The Master Trainers will use this manual for training tilapia hatchery technicians countrywide on how to improve biosecurity in hatcheries.