We reviewed CTs from 47 patients with 48 spontaneous, supratentorial brain hemorrhages to determine the effect of ventricular blood on outcome. We correlated volumetric analysis of the parenchymal (P) and ventricular (V) blood, as well as other clinical and CT features, with clinical outcome in a statistical analysis. Hemorrhages were located in putamen 20/48 (42%), thalamus 13/48 (27%), lobar 9/48 (19%), caudate 3/48 (6%), and miscellaneous locations 3/48 (6%). Outcome in putaminal hemorrhages was highly correlated with the total (P + V) and P blood volumes, whereas the V blood was less important. For thalamic hemorrhages, outcome correlated more highly with the V and P + V volumes than with the P portion. Outcome for all hemorrhages was significantly correlated, in descending order of importance, with the severity of the initial neurologic deficit, P + V blood, hydrocephalus, the number of ventricles containing blood, P, V, and blood in the 4th ventricle. In general patients with more than 20 cc of V blood did poorly. Although hydrocephalus was associated with poor outcome, ventricular drainage did not benefit 8 of 9 patients.