Objectives To examine the effect of weekend admission on short and long-term morbidity and mortality, for patients admitted to intensive care after suffering a cerebrovascular accident (stroke). Design, setting, and participants A hospital-wide, retrospective cohort study of 3,729 adult stroke patients admitted to the Beth Israel Deaconess Medical Centre (BIDMC) intensive care unit (ICU) between 2001 and 2012, using the Medical Information Mart for Intensive Care III (MIMIC-III) database. Primary outcome measures Primary outcome measures were ICU length-of-stay and mortality, hospital length-of-stay and mortality, proportions of patients discharged home after admission, and 6-month mortality. Results Overall, 23% of BIDMC ICU stroke admissions occurred over the weekend. Those admitted over the weekend were likelier to have suffered haemorrhagic stroke than those admitted during the week (60.6% vs 47.9%). Those admitted on the weekend were younger, and likelier to be male and unmarried, with similar ethnic representation. The OASIS severity of illness (32.5 vs. 32) and lowest day-one GCS (12.6 vs. 12.9) were similar between groups. Unadjusted ICU-mortality was significantly higher for patients admitted over the weekend (OR 1.32, CI 1.08-1.61), but when adjusted for type of stroke, became non-significant (OR 1.17, CI 0.95-1.44). In-hospital mortality was significantly higher for patients admitted to ICU over the weekend in both unadjusted (OR 1.45, CI 1.22-1.73) and adjusted (OR 1.31, CI 1.09-1.58) analyses. There was no significant difference in ICU or hospital length of stay.