Description: Ornithobacterium rhinotracheale (ORT) is a Gram negative, pleomorphic, rod-shaped and non-motile bacterial pathogen most known for causing respiratory tract infections in chickens. Ornithobacteriosis has been reported in almost all countries around the world. The objective of this study was to determine the prevalence of ORT in broiler flocks in southwest Iran. DNA was extracted from 230 collected tracheal swabs and lungs samples and amplified by ORT 16S rRNA gene specific primers using the PCR technique. ORT DNA was detected in 63 broiler chickens samples (27.39 percentage). The results of this study demonstrate the wide spread of ORT in broiler chickens and confirmed that infection with ORT was highly prevalent in southwest Iran