SummaryA 64-year-old white male with cavitary lung disease is presented.Mycobacterium aviumwas isolated from sputa and gastric lavage and the American Thoracic Society criteria for nontuberculous mycobacterial disease were met. Seven years follow-up and treatment regimens are discussed.This case illustrates that medical treatment of M.aviumpulmonary disease can be disappointing and requires regularclinical, radiological, microbiological and haematological reassessment to evaluate efficacy and toxicity of therapy.Despite in vitro resistance to the standard antimycobacterial agents, prolonged treatment regimens can be successful and are the therapy of choice. Another drug combination, based on in vitro susceptibility patterns, has to be started for patients who fail to respond or who relapse. Lifelong treatment may be necessary to keep the patient stable and to prevent further destruction of lung parenchyma.