In this study, the role of Brucella spp. in cattle and sheep abortions among Kayseri region was investigated and predominant subspecies and biovars in this region were determined by conventional and molecular biotyping methods. For this purpose, 61 cattle and 64 sheep abortion material and also 50 human blood isolates were examined. A total of 29 Brucella spp. 17 (27.9%) and 12 (18.7%) of which were isolated from cattle and sheep specimens, respectively) were isolated from animal sources. Both animal and human isolates were typed by conventional and Enhanced AMOS-ERY PCR methods. All Brucella spp. strains isolated from cattle were found to belong to B. abortus biovar 3 and biovar 3b using conventional and molecular typing methods, respectively. All sheep originated Brucella spp. strains and human originated Brucella spp. strains were found to belong to B.melitensis biovar 3 using both conventional and molecular methods. As a result, predominant biovars causing brucellosis in human, cattle and sheep in Kayseri, Turkey were detected. These findings were considered to be useful in prevention and controlling activities for Brucellosis in Turkey.