Pigeons are extensively kept for homing and racing purposes in Iran. The main objective of this study was to investigate dissemination of M. avium subsp. avium (MAA) in pigeon aviaries in Tabriz, North-western Iran.Postmortem pathologic specimens from thirty-nine out of 140 birds collected from private flocks (n=3), were subjected to bacterial culture out of which 3-4 mycobacterial isolates were recovered.Applying a five-PCR diagnostic algorithm targeting short but definitive stretches of 16S rRNA and RV0577 genes, IS6110, IS901 and IS1245 genomic loci, proved all the isolates were MAA. They were either IS901+/IS1245+(n=22) or IS901+/IS1245- (n=12). When four healthy cattle sensitized against Mycobacterium bovis AN5 and Mycobacterium avium D4 were tuberculinated, the results confirmed the observed skin reactions against bovine tuberculin in animals sensitized with M. avium were large enough to complicate test interpretation.We believe the extent of such epidemiological impact deserves further investigation if progress in control of bovine tuberculosis is intended.