RT-PCR assays for detection of BRSV, based on four different sets of primers were optimized and evaluated for their sensitivity and specificity. Primers used in this study were specific for genes encoding three BRSV proteins, nucleoprotein N and glycoproteins F and G. Our results indicated that RT-PCR with primers B7:B8 for G protein was the most efficient in detecting BRSV. Starters B7:B8 reacted specifically only with BRSV strains, no cross-reaction with other closely related viruses to BRSV was observed. RT-PCR sensitivity was also high and amounted to 10(1.66) TCID50. Starters for F and N genes of BRSV were not sufficiently specific and cross-reacted with RNA of HRSV. RT-PCR with primers for the genes F and N of BRSV was characterized by a lower sensitivity than RT-PCR with primers B7:B8. In conclusion, RT-PCR specific to a sequence of glycoprotein G gene, seemed to be the most useful for BRSV detection.