Background & aim Nutritional intake of patients in acute respiratory failure receiving non-invasive ventilation has not previously been described, and no protocols have been developed to guide practice to optimise nutritional status. We aimed to measure energy and protein intakes of patients in acute respiratory failure requiring non-invasive ventilation receiving standard hospital nutritional care. Methods Food and fluid intake forms were completed by nursing staff for all meals and mid meals for patients admitted with respiratory failure commencing on non-invasive ventilation. Intake was converted from quartiles of food consumed into energy and protein to enable comparison with estimated daily requirements using descriptive statistics. Multinomial stepwise regression analysis was used to determine factors associated with inadequate protein and energy intake. Results Over 283 total days of intake, 36 participants (67% female, aged 65 ᠹ years) achieved on average 1434 ᠶ27 kcal and 63 ᠲ9 g protein daily. Overall, 28 patients (78%, 95% CI: 61-90%) met less than 80% of estimated energy requirements and 27 patients (75%, 95% CI: 58-88%) met less than 80% of estimated protein requirements. Being fed orally, longer time on non-invasive ventilation and higher BMI were associated with poorer intakes. Better nutritional status on admission and measuring intake closer to hospital discharge was associated with improved intakes. Conclusion Patients with acute respiratory failure requiring non-invasive ventilation often had inadequate oral intake, particularly with increasing time on non-invasive ventilation, and earlier during their hospital admission. Development of protocols to optimise nutritional intake for these patients may improve outcomes and reduce regular readmission rates.