Before attempting weaning one has to assess whether the patient is ready for wean or not. A patient who has recovered from the underlying condition and has acceptable clinical and physiological parameters (weaning criteria) he / she, is ready for weaning from NIV. The clinical and physiological parameters used in this setting include -arterial pH ≥ 7.35, oxygen haemoglobin saturation (SpO 2 ) > 90% on FiO 2 ≤ 50%, respiratory rate ≤ 25 / min, heart rate ≤ 120 / min, systolic blood pressure ≥ 90 mmHg and no signs of respiratory distress like agitation, diaphoresis or anxiety. Patient satisfying these criteria, there can be three ways by which weaning from NIV may be done -stepwise reduction of duration of NIV use, stepwise reduction in pressure support and immediate withdrawal of NIV.