Between 1994 and early 1999, Mycobacterium xenopi was isolated in 11 HIV-negative patients seen at the Respiratory Disease Department of the Dijon University Hospital. Eight of these patients met the criteria of lung infection. Clinical and radiological features simulated pulmonary tuberculosis which delayed diagnosis until the germ was identified. Treatment is considered to be mandatory though it is difficult to manage and often disappointing. In spite of long-term medical care, sometimes associated with surgery, outcome is currently determined by the underlying disease rather than by Mycobacterium xenopi infection.