BACKGROUND: Mycobacterium avium subspecies Paratuberculosis (MAP) is a bacterium known to cause Johne's disease in ruminants and has been implicated in several autoimmune diseases. This study aimed to investigate the potential association between MAP infection and Rheumatoid Arthritis (RA). METHODS: A total of 119 patients with RA and 120 healthy controls (HCs) were enrolled in the study. The participants were outpatient attendees at a rheumatology specialist's clinic, selected according to the 2010 ACR/EULAR Classification Criteria for RA. Their serum samples were analyzed for antibodies against two peptides, MAP_4027 RESULTS: A significant difference was found in the levels of anti-MAP antibodies between RA patients and HCs. RA patients were more likely to have anti-MAP_4027 CONCLUSIONS: The study findings suggest that anti-MAP antibodies are more prevalent in RA patients compared to healthy controls, potentially implicating MAP in the development of RA. The strong immunological response to the antigen IRF5