The aim of the current study was to investigate the prevalence and the nature of swine mycobacteriosisin pigs raised under poor hygienic conditions in Egypt and to evaluate fibronectin-binding protein(Ag85-B) in serological detection of the disease in living pigs. A total of 745 slaughtered pigs were examined for suspected mycobacterial lesions. Lymph node specimens for mycobacteriological examination and blood samples for serological evaluation of Ag85-B were collected from both suspected and lesion-free pigs. The study revealed that 8.9% of examined pigs were infected with different Mycobacterium species, of which, 14.9% were multi-drug resistant. Serological evaluation of  Ag85-B revealed an overall sensitivity and specificity of 88.1% and 86.9%, respectively; as compared to 86.6% and 65.2% of tuberculin PPD-based serodignosis. In conclusion, the study revealed high burden of drug resistant mycobacterial infections in Egyptian swine and showed the reliability of Ag85-B as a potential candidate for serological diagnosis of swine mycobacteriosis in living pigs.