Background and Purpose— Early hematoma growth is one of the main determinants of mortality in patients with intracranial hemorrhage (ICH). Transcranial duplex sonography (TDS) might represent a useful tool for the bedside monitoring of early ICH enlargement. We aimed to correlate ICH volumes measured by TDS and CT scan in patients with ICH evaluated <3 hours of symptom onset. Methods— We prospectively studied 34 patients with supratentorial ICH evaluated <3 hours of onset. All patients underwent emergent CT scan and TDS examination on admission and at 6 hours. Major longitudinal, sagittal, and coronal hematoma diameters were measured on CT scan by a neuroradiologist and on TDS by a blinded operator with a time delay <30 minutes between both techniques. Total hematoma volume was determined using the formula for irregular volumes (longitudinal×sagittal×coronal)/2. Early hematoma growth was defined as an increase >20% in the hematoma volume at 6 hours. Results— ICH was identified on TDS as an hyperechogenic mass located in the basal ganglia in 28 patients and in the lobar position in 6. Mean hematoma volume at baseline was 86±4 5 mL. At 6 hours, early hematoma growth was seen in 9 (26%) patients. An excellent correlation was found between TDS and CT measurements for all diameters: longitudinal ( r =0.91, P <0.001), sagittal ( r =0.85, P =0.002), coronal ( r =0.79, P =0.022) and for total hematoma volume ( r =0.82, P =0.001). When all obtained measures were matched, the intraclass correlation coefficient was 0.888 (95% CI, 0.8 to 0.937). Conclusion— TDS showed an excellent correlation with CT in measuring the extent of bleeding in patients with hyperacute ICH. TDS may represent a reliable useful tool for monitoring ICH noninvasively at the patient’s bedside.