The goal of this study is to assess HFNC oxygenation and compare the efficacy of high-flow nasal cannula (HFNC) to noninvasive ventilation (NIV) on oxygenation in patients with acute hypoxemic respiratory failure. The patients were randomly grouped into two groups, 20 in each group. Group 1: treated by high-flow nasal cannula (HFNC) and group 2: treated by non-invasive ventilation. There was a statistically significant difference regarding P_aO₂/FiO₂ at baseline and at the end (P-value < 0.001) in both groups indicating improvement of oxygenation in both groups. There was a statistically significant difference between the two groups regarding the P_aO₂ and P_aO₂/FiO₂ ratio (P-value < 0.05) at the end of the trial however the degree of oxygenation improvement was significantly higher with NIV group. The conclusion of our study: the use of high flow nasal cannula is effective in improving oxygenation but NIV was superior to HFNC.