Atypical mycobacterial infections are increasingly important in immunosuppressed patients as well as in healthy hosts. The atypical mycobacterium that most commonly affects the skin is Mycobacterium marinum. The infection should be suspected upon the presence of ulcers, nodules or chronic plaques and a history of contact with fresh or salt water. Optimal therapy is yet to be established. We report a case of My-cobacterium marinum infection in a patient receiving immunosuppressive therapy that responded favourably to treatment with doxicycline. We review the different antibiotic regimens prescribed in the past years for the treatment of Mycobacterium marinum infection.