Introduction: Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction secondary to a systemic response to infection. The diagnosis is currently by exclusion. Objectives: to describe cerebral hemodynamic patterns, cerebral hemodynamic reserve (CHR) and the protein biomarker S100β in patients with SAE. Methods: a prospective, longitudinal and descriptive study was carried out in the intensive care unit of the Centro de Investigaciones Médicos Quirúrgicas, from January 2014 to March 2016 in 20 patients with SAE in which the cerebral hemodynamic pattern and CHR were determined by transcranial Doppler (TCD) sonography and the protein biomarker S100β. The study variables are related. Results: cerebral hemodynamic patterns most frequently found were: low flow and hyperemic, 35% respectively and cerebrovascular reserve capacity was variable (50% normal vs 50% decreased). The protein S100β was found to be elevated in 80% of the sample. The existence of hyperemic pattern, decreased cerebrovascular reserve capacity and high S100β protein was associated to mortality. Conclusions: in patients with SAE there is not a typical cerebral hemodynamic pattern nor CHR. The protein S100 β can be used as a marker of brain damage in SAE. The existence of the triad: hyperemic pattern, diminished cerebrovascular reserve capacity and high S100β protein is indicative of poor prognosis.