Association mapping (AM) is an alternative approach that may, in theory, overcome limitations of pedigree-based quantitative trait loci (QTL) mapping . It has been used in model species with available genomic resources, however with recently available genome sequences for forest species, this approach has the potential to increase the chance of understanding the genetic architecture of complex traits. The candidate-gene-based approach has been used for forest species where genome sequences were not yet developed . In our study, we conducted a genome wide association study (GWAS) to discover loci associated with BBD resistance. A case-control design was used, which compared marker frequencies between a group of affected individuals (cases) and a group of unaffected individuals (controls). In this approach, we aimed to examine genetic architecture of disease resistance in American beech and identify candidate genes associated to BBD. Once identified, a marker breeding based approach could be used in breeding programs for BBD resistance.