The authors present a case of multiple developmental venous anomalies (DVAs) that involved nearly the entire cerebral hemisphere and that were diagnosed by magnetic resonance (MR) imaging and selective cerebral angiography. The ipsilateral cerebral hemisphere was mildly atrophic, and there were focal white matter lesions on the MR images. Angiography showed multiple DVAs involving nearly the entire right cerebral hemisphere. We suggest that longstanding venous congestion caused the atrophy and white matter lesions.