Background: The success of non invasive ventilation depends on many factors and effective delivery requires team work. Information on the therapeutic program must be sustained by healthcare staff and family. Objectives: Investigate the clinical and care factors that affect the level of patient compliance to non invasive ventilation. Methods: A prospective, observational and multicentre study was conducted between November 1, 2015 and February 15, 2016 in three sub-intensive wards. A data collection tool was created with the working definition of "Patient intolerant to non invasive ventilation" and a structured interview was conducted to investigate patient experience of NIV. Statistical analysis was conducted with the STATA MP13 software. Results: Coordination of patient-ventilator interaction prevents intolerance (OR = 0.68, 95% IC 0.46 -0.98; P = 0.04). Overweight and obese patients showed a higher probability of intolerance to non invasive ventilation with respect to underweight and normal weight patients (OR = 0.53, 95% IC 0.34 -0.82; P = 0.005). Patients with a higher probability of intolerance experienced a NRS level