In this thesis a founder analysis of the Austrian Haflinger based on 57.012 individual pedigree recordswas conducted. Data was provided by the Association of the Haflinger Breeders Austriaand the Association of Haflinger Breeders Tirol. Preliminary to analysis the pedigree data was completed and the two databases were unified in the course of this thesis.For thefounder analysis and the determinationof the genetic variabilitywithin the Austrian Haflinger population, three reference populations (R1 2008 -2015; R2 1993 -2000; R3 1978 -1985) were defined. Based onthe actual size of breedingpopulation, the total number of founders, the effective number of foundersandthe effective number of ancestors, the current breeding population of the Austrian Haflinger (2008-2015) has the smallest gene pool andthe lowest genetic diversitywithin the three reference populations. The sizeof the breeding population continuously declined from the period 1978 to2015. If we compare the diversity parameters of reference population 3 and reference population 2, we see that the number of effective founders(fe)has decreased by almost 19 %(R3 fe=43; R2 fe= 35). A far as the number of effective ancestors(fa)is concerned, a decrease of 22 % from Ref. 2 (fa= 14) to Ref. 3 (fa= 18) can be noted. If we compare reference population 2 and reference population 1, we can see that the number of effective founders has decreased by 11 % (R1 fe= 31) and the number of effective ancestors has decreased by 14 %(R1 fa= 12). In the current breeding population (R3)four animals determine50 % of the gene pool. With regard to the genetic diversity of this population, calculations show that there are 31 effective founders and 12 effective ancestors. Thereforethe Austrian Haflinger showesthe lowest genetic diversitymeasures of Austrian horse breeds. In all three reference populations the stallions Hirn-Mandl I, 54 Genter and the Arabianstallion El Bedavi XXII range amongst the 15 most important founders which illustratesthe influence the Arabianhashad on the development of the Haflinger horse.