The microsatellites markers are developed for somme years now (Tautz & Renz, 1984). The high degree of polymorphism displayed, the relatively even distribution in the genome, the ease with which they can be analysed by PCR method and the fact that the markers can be readily be adopted and used by others research group (PCR Primer Reaction), has made microsatellites the marker of choice in genetic linkage group studies of eukaryotic species. Microsatellites were studied in different species in ·animais as weil as in plants. For example many species of fish weres studied using microsatellites like Salmo salar (Slettan, 1993, 1997 ; O'Reilly, 1996), Salmo trutta (Estoup et al, 1993) and Dicentrarchus labrax (Garcia de Leon, 1995). There are few microsatellites study on bivalves. Naciri (1995) published microsatellites results on flat oysters (Ostrea edulis). McGoldrick (1997) identified 30 microsatellites in the Pacifie oyster (Crassostrea gigas) but he has not used yet on oyster family. Three polymorphie loci in the Pacifie oyster were published by Magoula (in press). Sorne study were done using 4 microsatellites to compare C. gigas and C. angulata (Huvet, 1997),  microsatellites studies were used to evaluate the parental contribution in different cross in C. gigas (Baudry, in press; Hervouet, 1998). These latter studies (Huvet, 1997; Boudry, in press; Hervouet, 1998)  were done in IFREMER La Tremblade Laboratory. The aim of the training in IFREMER Laboratory in la Tremblade is to leam the microsatellites techniques on Crassostrea gigas . The microsatellites on C. gigas are used on routine now, there were developed in La Tremblade in co-operation with François Bonhomme from University of Montpellier (France). So four microsatellites markers were used and three others which has not been used in a population genetic study yet were tested. The individuals which were studied with microsatellites were also genotyped with allozymes in Galway (Ireland). These two techniques can be used on Crassostrea gigas family to built genetic map.