Abstract: Infectious bronchitis is a disease of an economical importance of chickens. As result of emerging of new variant strains, the prevention and control of the disease is difficult. The study is the first to be conducted in Saudi Arabia. Results showed that there is a wide-spread of IBV amongst chicken farms in the Riyadh Province. Using RT-PCR, viral RNA was detected in 35 (42.68%) out of 82 poultry farm houses from 42 farms investigated in this study. The highest viral detection (55.55%) was recorded in Shaqra governate while the lowest (20%) was in the Northern governates (AL-Zolfi, AL-Dwadmi and Hremla). Detection of IBV in vaccinated chickens was evident that some of the vaccines used in the field did not provide the adequate protection against the disease. This investigation showed that viral detection was successfully done in 29 (35.36%) out of 82 farm houses from 42 farms using the conventional method of sample collection while the detection rate dropped to 21.95% (18 farms) when Flinders Technology Associates (FTA) card were used. Interestingly enough, viral detection was found positive in 6 samples using the FTA card but was negative using the conventional method. For further identification and phylogeny, the amplified PCR products of 2 isolates were sequenced and analyzed for phylogenetic analysis and compared with other avialable IBV strains from the GenBank. First isolate was designed as IBV/CHICKEN/KSA/101/2010)with accession No. HQ916668 was found to share high nucleotide sequence identity (98.9%) for Nucleocapsid (N) protein genes with IBV/CH/LDL/01I sequence; a strain from China which may be revertant attenuated vaccine strains that have arisen as a result of the widespread use of IBV vaccines in the local poultry population in China. The second isolate was designed as IBV/CHICKENS/KSA/102/2010 with accession number HQ916669 was found to share a high degree of identity (99.7 and 99.5%) with the IBV/INDIA/TN/92/03 and IBV/HB/CH isolated in India and China, respectively. The phylogenetic analysis for the isolates were found highly diverse from the same sequences of IBV/H120 strain that commonly used as commercial vaccine for prevention of IBV in poultry flocks in KSA.