Introduction: out-of-hospital cardiac arrest is a public health issue worldwide. Neurological consultation and multimodal prognostic assessment has, nowadays, become an integral part of post- resuscitation patient management. Lymphopenia is associated with mortality in some diseases with both pro and anti-inflammatory immune mechanisms like sepsis. The aim of our study was to evaluate the association between lymphopenia and neurological outcomes after out-of- hospital cardiac arrest. Patients and methods: we performed a retrospective multicenter study including adult patients admitted to three intensive care units for out-of-hospital cardiac arrest. Management was performed in accordance with International liaison committee on rResuscitation (ILCOR) guidelines. We collected prehospital and intensive care demographic data. Various biological parameters were studied during the first 48 hours, including lymphocyte count. The neurological outcome of the patients was assessed by the Cerebral performance categories (CPC) score at discharge from ICU. Scores of 1 and 2 were considered as good outcomes and those of 3 to 5 as an unfavourable neurological outcome. Results: eight hundred and two patients were included, 230 with good neurological outcome and 570 considered to have a poor neurological prognosis. Demographic data were similar between groups. In our population, 40% had lymphopenia at admission. It occurs more often in patients with good neurological outcomes, with a lower lymphocyte count. However, there was a higher decrease of lymphocytes during the first 48 hours in the group of patients with poor neurological outcomes. Conclusion: lymphopenia on admission to critical care after out-of-hospital cardiac arrest is present in less than a half of cases and is rather associated with a favorable outcome. On the other hand, a greater decrease in the lymphocyte count in the first 48 hours is associated with a poor neurological outcome. Further studies are needed to validate this parameter.