The noble scallop Chlamys nobilis (Reeve) is one of the most economically important fishery and aquaculture species along the southern coast of China.Selective breeding is a common and effective technique that has been widely applied in genetic improvement of aquaculture stocks.Although the noble scallops have been cultured in China for several decades, there have no well-documented cases of selective breeding.To determine whether genetic improvement can be attained through a selective breeding programme, we conducted a one generation mass selection for shell length in a cultured noble scallop stock.The stock, which has been successively cultured in China for about 10 years (6 generations), descended from a wild population in Leizhou Peninsula, Zhanjiang, Guangdong Province, China.