There was a strong positive correlation between the plasma level of NT-proBNP and the National Institutes of Health Stroke Scale score (r=0.415, P=0.000). Plasma levels of NT-proBNP in patients with an unfavorable outcome were significantly higher than those in patients with a favorable outcome [3432 (interquartile range, 1100-54991) vs. 978 (interquartile range, 123-1705) pg/ml; P=0.000]. In multivariate analyses, after adjusting for all other significant outcome predictors, the NT-proBNP level that remained can be seen as an independent unfavorable outcome predictor, with an adjusted odds ratios of 4.14 (95% confidence interval, 2.72-7.99; P=0.000). Our results show that plasma NT-proBNP levels were significantly elevated in patients with an unfavorable outcome and might be of clinical importance as a supplementary tool for the assessment of functional outcomes in patients with AIS.