Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by widespread localization of calcispherites in the alveolar spaces. The patients are symptomless for a long time. Nevertheless, this disease slowly develops into pulmonary fibrosis and cardiac failure. The chest X-rays and high-resolution computed tomography strongly point towards a diagnosis of PAM. As for therapeutic approaches, repeated broncho-alveolar lavages (BAL) have been performed with improvement of symptoms but without recovery, and a new oral drug treatment is still under way. We report 2 familial cases of PAM. Both patients underwent chest X-ray examination showing diffuse bilateral micronodular opacities of calcific density. After 5 years, in May 1993, one of them developed exertional dyspnoea, cyanosis, dry cough and was admitted to our Division. Cardiokinetic and diuretic drugs as well as oxygen were administered with satisfactory results. Then repeated BAL were performed. The chest X-ray after 6 months of sodium etidronate (300 mg t.i.d.) administration was unchanged.