Background: Right ventricular dysfunction (RVD) is frequent in patients suffering from acute respiratory distress syndrome (ARDS). Veno-venous extracorporeal membrane oxygenation (V-V ECMO) may allow the use of ultraprotective mechanical ventilation (MV) in the most severe cases of ARDS. However, the effects of this MV strategy on RV function are not well known. We investigated with echocardiography the prevalence and evolution of RVD in patients supported with V-V ECMO for severe ARDS and ventilated with an ultraprotective ventilation approach. Methods: Eighteen patients who required V-V ECMO for severe ARDS and were assessed with echocardiography before and after cannulation between January 2014 and December 2017 were enrolled in this retrospective observational study. Results: Before cannulation, RV dilatation was present in 6/16 (37%) and 10/17 (59%) patients, according to quantitative and qualitative assessment, respectively, and RVD was reported in 9/14 (64%) patients. After cannulation, tidal volume, plateau pressure, and driving pressure significantly decreased [median (interquartile range) values were 2.0 (0.9-3.6) mL/kg, 20 (20–20) cmH2O, and 10 (10–10) cmH2O, respectively] and RV size and function were similar as before cannulation. Except for SaO2 before cannulation, which was significantly lower in non-survivors, no other risk factor for RVD, RV dilatation, or mortality was identified in our population. Conclusions: In patients requiring V-V ECMO for severe ARDS, RVD and dilatation before ECMO cannulation were frequent but not associated with worse clinical outcomes. An ultraprotective MV strategy was not accompanied by a worsening of RV function.