BACKGROUND: We ascertained the occurrence of global cerebral edema manifesting as increased brain volume in subjects with intracerebral hemorrhage (ICH) and explored the relationship between subject characteristics and three month outcomes. METHODS: A post-hoc analysis of a multicenter prospective study that recruited patients with ICH, elevated SBP >/=170 mm Hg, and Glasgow Coma Scale (GCS) score >/=8, who presented within 6 h of symptom onset was performed. Computed tomographic (CT) scans at baseline and 24 h, submitted to a core image laboratory, were analyzed to measure total brain, hematoma, and perihematoma edema volumes from baseline and 24-h CT scans using image analysis software. The increased brain volume was determined by subtracting the hematoma and perihematomal edema volumes from the total brain volume. RESULTS: A total of 18 (44 %) of 41 subjects had increased brain volume that developed between initial CT scan and 24-h CT scan. The median increase in brain volume among the 18 subjects was 35 cc ranging from 0.12 to 296 cc. The median baseline GCS score was 15 in both groups of subjects who experienced increased brain volume and those who did not, and the median hematoma volume was 10.18 and 6.73, respectively. Three of the 18 subjects with increased brain volume underwent concurrent neurological deterioration and one subject died during hospitalization. CONCLUSIONS: We found preliminary evidence of increased cerebral brain volume in subjects with good grade and small ICHs, which may be suggestive of global cerebral edema.