The goals of this work were to investigate whether elevated total homocysteine (tHcy) measured within 24 hours of acute stroke was an independent risk factor for recurrent stroke and to compare levels of tHcy in groups of patients with diagnoses of ischemic and hemorrhagic cerebrovascular events. We performed a longitudinal study of 1039 stroke patients (mean age, 75 years). Fasting tHcy was measured the morning after primary admission. Patients were followed up for 15 months. Serum homocysteine was significantly higher in the 105 patients who experienced a recurrent stroke during the follow-up period than in patients without recurrence. The geometric mean+/-SD was 13.4+/-10.7 versus 11.8+/-7.1 micromol/L (P=0.008), and the mean difference was 1.2 micromol/L 95% confidence interval (CI), 1.05 to 2.3. In a multiple logistic regression model, tHcy was an independent explanatory variable of recurrent stroke within 15 months (odds ratio, 1.3; 95% CI, 1.1 to 1.5) for each increase in tHcy of 10 micromol/L. At the index event, serum homocysteine was significantly higher in 909 patients with ischemic cerebrovascular events than in 130 patients with intracerebral hemorrhage (geometric mean, 12.1+/-7.3 versus 10.4+/-5.2 micromol/L; P<0.001). The data in this study indicate that elevated tHcy is an independent risk factor for recurrent stroke.