Background: Malnutrition is thought to affect 30% to 70% of hospitalized patients. Little is known about consequences of undernutrition during the acute phase of stroke. We would like to assess the impact of pre-infarction malnutrition on stroke patients treated with thrombolysis and/ or thrombectomy. Material and methods: We performed a retrospective observational study on a cohort of stroke patients who benefited from thrombolysis and/ or thrombectomy during 2015 in Saint Joseph Hospital’s Stroke Unit. The main objective of our research was to observe the clinical course of undernourished patients compared to the non-undernourished ones, using the NIHSS score at the stroke unit discharged and the 3 months modified Rankin score. Undernutrition was defined by a body mass index of (BMI) ≤ 21. Results: A total of 81 patients with thrombolysis and/or thrombectomy treatment were included. The median BMI in < 70-year-old patients was 24.5 and 25 in > 70-year-old patients. Initial severity measured by baseline NIHSS score was comparable among the undernourished and non-undernourished patients. Undernourished patients over 70 had a more severe neurological state at discharge (NIHSS 8.5 versus 3.9, NS) and were more disabled 3 months after discharge (Rankin 3.1 versus 2, NS). Conclusions: Undernutrition prior to stroke seems to have an impact on the functional prognosis of cerebral infarction, especially in patients > 70 years of age. Lack of significant results may be explained by the limited statistical means. A complementary study with a larger cohort is planned in order to assess this hypothesis.