['Prenotification to hospitals by emergency medical services of patients with suspected stroke is recommended to reduce delays in time-dependent therapies. We hypothesized that hospital prenotification would reduce recommended stroke time targets.', 'We used the Robert Wood Johnson University Hospital (RWJUH) Brain Attack Database, which includes demographic and clinical data on all emergency department (ED) patients alerted as a Brain Attack between January 1, 2009 and June 30, 2010. Outcome variables included the time from door to stroke team arrival, computed tomographic (CT) scan completion, CT scan interpretation, electrocardiogram, laboratory results, treatment decision, and intravenous (IV) tissue plasminogen activator (tPA) administration. The primary independent variable was brain attack activation before arrival to the emergency department (ED; prenotification) versus on or after ED arrival (no prenotification). Analysis of covariance was used with patient predictors as covariates in addition to the one of interest (prenotification vs no prenotification). P ≤ .05 was considered statistically significant.', 'There were 229 patients (114 prenotification and 115 no prenotification) alerted as having a brain attack within the study period. Patients with prehospital notification were older (69.5 years vs 61.5 years; P = .0002), had more severe strokes (National Institutes of Health Stroke Scale score of 11.1 vs 6.9; P < .0001), and received IV tPA twice as often (27% vs 15%; P = .024). Prenotification resulted in a significant reduction in all stroke time targets except door to treatment decision and tPA administration.'] Does hospital prenotification of stroke patients by emergency medical services improve stroke time targets?