Levels of C-reactive protein (CRP) and white blood cell count (WBC) in acute stroke may reflect the stroke lesion itself or pre-existing factors such as infections, smoking or atherosclerosis. The aim of this study was to investigate the relation between CRP and WBC levels and time from onset of stroke, stroke severity and outcome. The analyses were based on 719 patients in whom WBC test material was obtained within 9 h of stroke onset and CRP test material within 24 h of stroke onset. Stroke severity was assessed by the Scandinavian Stroke Scale Score on admission and outcome by death 7 days, 3 months and 1 year after symptom onset as well as modified Rankin Scale 3 months after stroke onset. CRP and WBC levels correlated significantly with time from symptom onset as well as with stroke severity and outcome. Levels of CRP and WBC were higher in later determinations in severe stroke. In multivariate logistic regression analysis, CRP(+10 mg/l) was independently related to 1-year mortality (OR 1.1, 95% CI 1.02-1.2). Levels of WBC and CRP increase within the first 24 h in patients with severe stroke. CRP but not WBC is related to long-term mortality possibly by reflecting the vascular risk profile.