Introduction: Patients with heart failure developing acute pulmonary oedema benefit from immediate administration of noninvasive respiratory support such as continuous positive airway pressure (CPAP) or Biphasic positive airway pressure (BIPAP). Objective: To quantify the most advantageous positive end-expiratory pressure (PEEP) required to improve patient's oxygenation and to evaluate outcome of noninvasive respiratory support in patients with cardiogenic pulmonary oedema. Methods: This was a nonrandomised interventional study. Patients admitted with acute cardiogenic pulmonary oedema to the cardiac intensive care unit were initiated on CPAP/ BIPAP mode of ventilation noninvasively. They were evaluated for the most advantageous PEEP that improved their symptoms. Results: A total of thirty two patients were studied. Twenty four patients were included in the CPAP group [mean (± SD) age of (63.66 ± 11.18) years)] and eight in BIPAP group [mean (± SD) age of (67.25 ± 12.6) years]. Most advantageous PEEP (mean (± SD) in CPAP group was 5.62 ± 1.24 cm H₂O and in BIPAP group was 7.125 ± 1.8 cm H₂O (P = 0.0125). Lower serum bicarbonate levels were found at baseline in the BIPAP group (14.4 ± 6.3 mmol/L) compared to CPAP group (19.4 ± 5.59 mmol/L, P < 0.041). Patients in BIPAP group needed a longer hospital stay (19.62 ± 14.9 days) compared to CPAP group of 8.12 ± 6.58 days (P 0.0047). Conclusions: Most patients of cardiogenic pulmonary oedema can be managed noninvasively with CPAP but patients with metabolic acidosis are likely to require BIPAP and a longer duration of hospital stay.