The medical indications of tracheostomy comprise the alleviation of upper airway obstruction; the prevention of laryngeal and upper airway damage due to prolonged translaryngeal intubation in patients subjected to prolonged mechanical ventilation; and the facilitation of airway access for the removal of secretions. Since 1985, percutaneous tracheostomy (PT) has gained widespread acceptance as a method for creating a surgical airway in patients requiring long-term mechanical ventilation. Since then, several comparative trials of PT and surgical tracheostomy have been conducted, and new techniques for PT have been developed. The use of percutaneous dilatation techniques under bronchoscopic control are now increasingly popular throughout the world. Tracheostomy should be performed as soon as the need for prolonged intubation is identified. However a validated model for the prediction of prolonged mechanical ventilation is not available, and the timing of tracheostomy should be individualized. The present review analyzes the state of the art of PT in mechanically ventilated patients--this being regarded by many as the technique of choice in performing tracheostomy in critically ill patients.