OBJECTIVES: To estimate the costs for the first clinically diagnosed stroke, in Spain. METHODS: Observational prospective study conducted in 16 Spanish centers (CONOCES study; Costes Socioeconómicos del Ictus en España). Patients will be followed during a 1 year period; 3 visits will be performed (inpatient hospitalization due to stroke, 3 and 12 months after stroke). Patient inclusion was controlled by the presence of Atrial Fibrilation (AF). Currently, hospitalization data from the first visit has been collected including patients’ demographics, stroke severity, patient status and QoL at discharge, and direct resource consumption: length of stay, imaging and laboratory tests, specific therapeutic interventions (thrombolysis, decompressive craniectomy, angioplasty…), supporting therapies, and medication. Unitary costs were obtained from national healthcare databases and the Spanish Catalogue of Medicinal Products (€, year 2011 values). RESULTS: A total of 322 patients were recruited from November 2010 to May 2011. Preliminary results from the first visit showed the following characteristics: 50.3% had AF, mean age of 71.95+11.57, 44.6% female, 28.6% with intravenous thrombolysis, NIH 6.72+8.11, modified Rankin Score 3.04+1.85, Barthel index 56.71+38.68. Mortality rate during stay was 6.2%. Only 257 patients were evaluable for economic purposes. Mean length of hospital stay was 9.65 days (95%CI, 8.71-10.60). Mean inpatient cost per patient was €6428 (95% confidence interval [CI], €5912-€6943). The most relevant categories of costs were inpatient hospitalization (€3960, 95%CI, €3574-€4347, 61.6% of direct hospitalization costs), specific therapeutic interventions (€984, 95%CI, €783-€1185, 15.3%), imaging tests (€951, 95%CI, €878-€1024, 14.8%), medication (€302, 95%CI, €209-€394, 4.7%), laboratory tests (€145, 95%CI, €126-€164, 2.3%), and supporting therapies (€86, 95%CI, €45-€127, 1.3%). CONCLUSIONS: The inpatient economic burden of stroke in Spain is substantial because of long hospital stays and other health resource utilization. Results from this study show higher costs than previously published data.