Basic information on the genetics of the pearl oyster is described for producing pearls with a better quality by scientific breeding of this interesting and important aquaculture species of mollusk. Reduction of resources, caused mainly by overfishing, has motivated the production of seeds in hatcheries and the breeding of stocks. Shell coloration is a trait that can be easily recognized and its inheritance has been studied. Strains with a white prismatic layer and those with a non-yellow pearl layer of shell have been experimentally produced by selective breeding. Shell size has also been improved in selection experiments. Experiments on hybridization and inbreeding depression were conducted to estimate the combining ability for crossbreeding and the effect of inbreeding in selective breeding. Triploid pearl oysters were produced experimentally, by treating fertilized eggs with chemical or physical shocks, and evaluated for their aquaculture potential. The growth rate to mostly sterile triploid animals improved after the maturation stage of the life cycle whereas some of the triploids produced abnormal gametes. Further studies should be focused on gametogenesis and other important physiological characteristics for the application of triploidy to aquaculture.