Brucellosis is primarily a disease of animals that can be transmitted to humans (zoonosis). Brucella is lack of classic virulence factors and tend to invade and chronic infection in host. Brucellosis is an occupational disease which infects more ranchers, farmer, slaughter, veterinarians and laboratory personnel. The aim of this study was to evaluate the prevalence of cep gene of Brucella isolated from clinical specimens in hospitals from Kermanshah of Iran. Of 100 serum specimens from patients referred to hospitals of Kermanshah in 2014 year were collected. These specimens were positive for Wright test (Ã1/80) and as well as they were verified by culture and biochemical tests. The cep sequence was attained from gene bank and the sequence was assessed to characterize and verifying the complete similarity (Alignment). For extraction of DNA from specimens, the kit from Cinnagen Company was applied. Then PCR test was performed and results analyzed by SPSS software. PCR reaction was performed for survey the presence of the pertinent gene in 100 specimens isolated from hospitals of Kermanshah, Iran. Among 100 clinical isolates of Brucella, 54 (54%) had cep gene. 75 cases (75%) of patients were males and females, respectively. According to the first time in this study was revealed the cep gene for diagnosis of brucellosis in the serum. So, cep gene can be used as a diagnostic component with other factors; however; this finding should be studied in animal models and diagnostic and therapeutic strategies linked with this gene will be also investigated.