Pulmonary alveolar proteinosis (PAP) is a rare disease in the field of pulmonary medicine. The efficacy of whole-lung lavage (WLL) as the treatment of PAP had never been evaluated in the Iranian population. Therefore, there is a real need to investigate the characteristics of PAP and also to evaluate the efficacy of WLL in this rare disease. The study aimed to investigate demographic features, clinical presentation and treatment outcomes of the disease in Iranian PAP patients.