Take-all disease caused by Gaeumannomyces species bring about economic loses in turfgrass cereals. Surveys were conducted in turfgrass areas in Turkiye and isolations were done from the 318 samples which were taken from irregularly shaped chlorotic patches, and the roots of which are close to dark brown or black. As a consequence of the isolations, fourteen Gaeumannomyces spp. were isolated, and then identifications were performed with rDNA sequence analysis using primers ITS1 and ITS4. Comparison of the ITS sequences with the isolates in the GenBank database, and phylogenetic analysis showed that the isolates belonged to Gaeumannomyces graminis var. graminis, Gaeumannomyces californicus and Gaeumannomyces cylindrosporus. As a result of the pathogenicity tests, virulence of G. graminis var. graminis and G. californicus isolates were higher than that of G. cylindrosporus. Disease severity rates caused by the isolates, as a result of in vitro trials were between 11.83-97.61%, and those in in vivo ranged from 3.70-89.64%. As a result of in vivo tests, it was detected that the most virulent isolate was G. graminis var. graminis numbered 732 followed by 966, 1345, 1369, 1385 and G. californicus numbered 1573, 1925. In this study, the effects of Chaetomium globosum, C. bostrychodes, Sordaria fimicola, Clonostachys rosea, Trichoderma harzianum and T. hamatum fungi, which were previously determined as endophyte species in turfgrass areas, against the most virulent species G. graminis var graminis, were also investigated. As a result of biological control studies, efficacy of C. globosum CG071, Chaetomium bostrychodes CB07-2, Trichoderma hamatum Tha34-2 and Trichoderma harzianum TH06-5 strains were found as 86.31%, 83.25%, 70.07, and 64.01% respectively. These strains were found promising in the biological control of 'take-all disease' caused by G. graminis var graminis in turfgrass areas.