This study was conducted to detect the serotypes Arkansas, Connecticut, Beaudette and Florida in broiler chicken farms in Fars province of Iran. The samples were obtained from 32 broiler chicken farms experiencing respiratory signs with high mortality and clinically diagnosed as avian infectious bronchitis. Total RNAs were extracted from the scrapped mucosa of tracheas and RT-PCR tests were performed using different types of primers including Del1 (F, R), (XCE-1, 2), (XCE-3 & BCE-1), (XCE-3 & MCE-1), S1 OLIGO (F, R) and S1 OLIGO NEW (F, R). Infectious bronchitis virus was detected in 72% poultry farms. The serotypes 4/91 and Massachusetts were detected in 47.9 and 21.8% farms, respectively, but the serotypes in 7 farms remained unclear. The results showed that there is no evidence for the presence of serotypes Arkansas, Connecticut, Beaudette and Florida in broiler chicken farms in Fars province of Iran.

Key words: Broiler chicken, Infectious bronchitis virus, Iran, Massachusetts, RT-PCR, Serotype 4/91