Samples from 717 sheep of 11 Austrian sheep breeds were genotyped for 25 microsatellite loci. Twenty-one loci showing no deviation from Hardy-Weinberg equilibrium were used to calculate pairwise genetic distances (Nei's minimum distance and Reynolds' distance). All breeds could be clearly distinguished through these genetic distances. The shortest genetic distance was found between Alpines Steinschaf (AS) and Waldschaf (WS). Within the so-called 'Steinschaf' group [AS, Montafoner Steinschaf (MS), Krainer Steinschaf (KS) and Tiroler Steinschaf (TS)] the MS adopted an extreme status with the largest distance to the other breeds in the group. This finding resulted in the decision to consider the MS no longer as subpopulation of Alpines Steinschaf but as an independent breed. A correct breed assignment using a Bayesian approach was possible for only 66% of all individuals belonging to Alpines Steinschaf, but for at least 90% of individuals for all other breeds investigated.