We have studied 506 Amerindians from three French Guiana groups: 194 Wayampi, living in Trois-Sauts, and 100 living in the Camopi area; 47 Emerillon also living in the Camopi area and 165 Wayana living on the Litani and Maroni rivers. All samples were tested for G1M (1,2,3,17), G3M (5,6,10,11,13,14,15,16,21,24,28) and KM(1) by the classical method of hemaglutination inhibition. The phenotype and haplotype distributions are presented and have been subjected to factorial analysis of correspondence. Two common GM haplotypes are GM1,17:21,28 and GM1,2,17;21,28 but with an important variation in frequency. A rare haplotype, GM1,17;21R,28, probably the result of a genetic anomaly, is frequent in the Emerillon (17%). These populations show no evidence of Negroid or Caucasian admixtures.