Musculoskeletal manifestations of atypical Mycobacterium are very rare and they can be easily missed by the junior doctors. We are presenting two cases of atypical Mycobacterium: the first one was infected by cleaning a fish tank and the other was immune-compromised patients. Both the cases were treated with broad spectrum antiboitics initially, with no results, unless the specimen cultures were obtained surgically and the specific cultures were asked. The treatment was started after obtaining the culture results. Both the patients were started on antituberculous treatment for 3 - 6 months with good functional results.