Pulmonary alveolar proteinosis (PAP) is a rare condition characterized by excessive amounts of surfactant phospholipids and proteins within the pulmonary alveoli. Depending on the amount of surfactant in the alveoli, varying degrees of disturbed gas exchange develop. We report the case of a middle-aged man presenting with fever, dyspnoe, cough and bilateral alveolar infiltrates on chest X-ray. On the basis of pink staining periodic acid-Schiff (PAS) of the milky material recovered from the airways during bronchoscopy, and transbronchial biopsies demonstrating normal interstitial structures, a diagnosis of PAP was established. He has been repeatedly treated with whole lung lavage--totally eight treatments- during a 30-month-period. The effect of therapy was excellent initially, but his symptoms recur, and he now needs treatment with shorter time-intervals. On the basis of this case history, an overview of the pathogenesis, clinical presentation, diagnosis, existing treatment modalities and prognosis of PAP is given.