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Background This study aimed to compare ventilatory parameters recorded in the first days of acute respiratory distress syndrome (ARDS) and mortality at day 60 between coronavirus disease 2019 (COVID-19) and influenza ARDS patients with arterial oxygen tension (PaO2)/inspiratory oxygen fraction (FIO2) ≤150 mmHg. Methods We compared 244 COVID-19 ARDS patients with 106 influenza ARDS patients. Driving pressure, respiratory system compliance (Crs), ventilator ratio, corrected minute ventilation (V′Ecorr) and surrogate of mechanical power (index=(4×driving pressure)+respiratory rate) were calculated from day 1 to day 5 of ARDS. A propensity score analysis and a principal component analysis (PCA) were performed. Results On day 1 of ARDS, COVID-19 patients had significantly higher PaO2/FIO2 (median (interquartile range) 97 (79–129.2) versus 83 (62.2–114) mmHg; p=0.001), and lower driving pressure (13.0 (11.0–16.0) versus 14.0 (12.0–16.7) cmH2O; p=0.01), ventilatory ratio (2.08 (1.73–2.49 versus 2.52 (1.97–3.03); p<0.001), V′Ecorr (12.7 (10.2–14.9) versus 14.9 (11.6–18.6) L·min−1; p<0.001) and index (80 (70–89) versus 84 (75–94); p=0.004). PCA demonstrated an important overlap of ventilatory parameters recorded on day 1 between the two groups. From day 1 to day 5, repeated values of PaO2/FIO2, arterial carbon dioxide tension, ventilatory ratio and V′Ecorr differed significantly between influenza and COVID-19 patients in the unmatched and matched populations. Mortality at day 60 did not differ significantly after matching (29% versus 21.7%; p=0.43). Conclusions Ventilation was more impaired in influenza than in COVID-19 ARDS patients on the first day of ARDS with an important overlap of values. However, mortality at day 60 did not differ significantly in the matched population.