Ocurrence of Pulmonary Alveolar Proteinosis (PAP) is reported in two siblings. The patients were both females diagnosed at 13 months and 1 month. Gastrointestinal symptoms with vomiting and failure to trhive started in the firts weeks of life. Impaired cell-mediated immunity was well documented in both girls. The older sister is at present 12 years old; her clinical evolution in stationary. The youngest died at six months of age due to rapidly progressive respiratory involvement. Six kindreds with familial ocurrence of PAP involving a total of 15 cases including ours, are reviewed. The mortality rate was 73 per cent. We tabulate sex, race, consanguinity, onset of initial symptoms, age of the diagnosis, clinical course, proven immunity disturbances, microbiological findings and health status in all cases. We discuss the clinical features of PAP and therapeutic approaches.