Mechanical ventilation is in general indicated where established or impending respiratory failure exists. Respiratory failure occurs when pulmonary gas exchange is sufficiently impaired to cause hypoxaemia with or without hypercarbia. The respiratory failure is classified into two broad categories: Type 1 (or hypoxaemic) and Type 2 (or hypercarbic) respiratory failure. This chapter talks about mechanical ventilators, airway pressure, and flow and derived volumes. The different modes of ventilation are: volume control ventilation, pressure control ventilation, mandatory breaths and spontaneous breaths. The chapter reviews alternative ventilation modes, practical aspects of mechanical ventilation, and complications of mechanical ventilation. It explains different ventilatory strategies for specific conditions such as acute lung injury/acute respiratory distress syndrome, chronic obstructive pulmonary disease, acute asthma and brain injury. A care bundle approach for the care of a ventilated patient should include thromboprophylaxis, gastric protection and evaluation of sedation status.