ABO, RH, MN, Kell, P, Lutheran, Lewis, HP, GC, ACP, PGM1, ADA and ESD markers were studied in 122 Valachian Gypsies from Vinodol in West Slovakia. The Valachian Gypsies represent about 5% of the total number of Gypsies (400,000) living in the Czech and Slovak Republic. The results show that their gene pool differs greatly from the one obtained for other Gypsy populations. Since Valachian Gypsies form an endogamous isolate with a high degree of inbreeding, genetic drift and founder effect might have contributed to this difference.