Background and Purpose— Although the computed tomographic angiography spot sign performs well as a biomarker for hematoma expansion (HE), computed tomographic angiography is not routinely performed in the emergency setting. We developed and validated a score to predict HE-based on noncontrast computed tomography (NCCT) findings in spontaneous acute intracerebral hemorrhage. Methods— After developing the score in a single-center cohort of patients with intracerebral hemorrhage (n=344), we validated it in a large clinical trial population (n=954) and in a multicenter intracerebral hemorrhage cohort (n=241). The following NCCT markers of HE were analyzed: hypodensities, blend sign, hematoma shape and density, and fluid level. HE was defined as hematoma growth >6 mL or >33%. The score was created using the estimates from multivariable logistic regression after final predictors were selected from bootstrap samples. Results— Presence of blend sign (odds ratio, 3.09; 95% confidence interval [CI],1.49–6.40; P =0.002), any intrahematoma hypodensity (odds ratio, 4.54; 95% CI, 2.44–8.43; P <0.0001), and time from onset to NCCT <2.5 hours (odds ratio, 3.73; 95% CI, 1.86–7.51; P =0.0002) were predictors of HE. A 5-point score was created (BAT score: 1 point for blend sign, 2 points for any hypodensity, and 2 points for timing of NCCT <2.5 hours). The c statistic was 0.77 (95% CI, 0.70–0.83) in the development population, 0.65 (95% CI 0.61–0.68) and 0.70 (95% CI, 0.64–0.77) in the 2 validation cohorts. A dichotomized score (BAT score ≥3) predicted HE with 0.50 sensitivity and 0.89 specificity. Conclusions— An easy to use 5-point prediction score can identify subjects at high risk of HE with good specificity and accuracy. This tool requires just a baseline NCCT scan and may help select patients with intracerebral hemorrhage for antiexpansion clinical trials.