The aim of this investigation was to analyze the effects of microhabitats and forest fragmentation on the composition and species abundance of a ground beetle community from three different beech forest patches on Mt. Osogovo (Macedonia), as well as to analyze the mobility (based on mark-recapture of individuals) and seasonal dynamics and sex ratio of the ground beetle community. The study site included three localities (A, B, C), one of them fragmented (A), with four microhabitats (open area, ecotone, forest stand, and forested corridor). Ground beetles were collected using pitfall traps during four sampling months (June-September 2009) that were operational for three continuous days per month. Species richness, abundance, diversity, homogeneity, and dominance were compared between the localities. Dissimilarities in carabid assemblages between localities and microhabitats were analyzed with Bray-Curtis UPGMA cluster analysis. In total 1320 carabid individuals belonging to 19 species were captured. The carabid assemblage structure of the continuous forest locality was substantially different from the other two smaller forest patches, indicating that microhabitat structure affects ground beetle communities through changes of species composition and richness.