Meconium aspiration syndrome (MAS) is found in 0.2-6 per 1000 lifeborn neonates. Aspiration of meconium particles may occur before, during or after delivery, associated with deep inspiratory movements due to fetal depression. Aspiration of meconium may cause mechanical obstruction of the airways, chemical pneumonitis, and surfactant inactivation. The disease is commonly associated with the development of pulmonary hypertension and severe respiratory insufficiency. MAS may be prevented, at least in some infants, by appropriate suctioning at birth. Great progress has been made in the treatment: early administration of surfactant improves gas exchange in many neonates. High frequency oscillatory ventilation, NO-inhalation and extracorporal membrane oxygenation have a role in severe respiratory failure.