We aimed to identify factors associated with hospital mortality among patients receiving extracorporeal life support (ECLS). All consecutive patients treated with ECLS for refractory cardiac arrest or shock in the Caen University Hospital in northwestern France during the last decade were included in a retrospective cohort study. Sixty-four patients were included: 29 with refractory cardiac arrest and 35 with refractory shock. The main reasons for ECLS were acute coronary syndrome (n = 23) and severe poisoning caused by drug intoxication (n = 19). At ECLS initiation, the left ventricular ejection fraction was 16% (±11). Initial blood test results were arterial pH = 7.19 (±0.20) and plasma lactate = 8.02 (±5.88) mmol/L. Forty (63%) patients died including 33 under ECLS. In a multivariate analysis, two factors were independently associated with survival: drug intoxication as the reason for ECLS (adjusted odds ratio [AOR], 0.07; 95% confidence intervals [CI], 0.01-0.28; p < 0.001) and arterial pH (an increase of 0.1 point [AOR, 0.013; 95% CI, <0.001-0.27; p < 0.01]). This study supports early ECLS as a last resort therapeutic option in a highly selected group of patients with refractory cardiac arrest or shock, in particular before profound acidosis occurs and when the cause is reversible.