Silver barb (Puntius gonionotus Bleeker 1850) is an Asian carp that is popular as a food fish. It is distributed throughout Thailand in rivers, canals, reservoirs and swamps. It is also cultured in ponds and paddy fields. Its production from aquaculture in 2003 was estimated at 49,066 f metric tons (14 per cent of the total fish production), and valued at 34.6 millions US dollars, ranking third among freshwater fishes cultured in Thailand. However, the performance of many hatchery populations of silver barb is low, mainly due to a lack of improved stocks. Preliminary results indicate that relative to local available stocks, a Silver barb strain in the Chao Phraya (CP) River has a higher growth potential, and that there is substantial additive genetic variation in body traits, suggesting that performance of this species may be improved by selective breeding. In view of this situation, a selection program for increased growth rate in CP Silver barb strain was started in 1998. In this paper, we describe the program and present the results on the achieved response to selection.