1. Cerebral blood flow of nine methamphetamine abusers with technetium-99m-hexamethylpropyleneamine oxime (HMPAO) and single photon emission computed tomography (SPECT) as well as morphological examination with magnetic resonance imaging (MRI) were investigated. 2. Six of these subjects exhibited multiple focal perfusion deficits in cerebral cortices without abnormalities in MRI including cerebral atrophy and/or infarctions. 3. Cerebral perfusion deficits were detected in methamphetamine abusers even after a long abstinence period, suggesting that vascular changes were irreversible to some degree. 4. HMPAO SPECT study appeared to be sensitive to the detection of cerebral perfusion abnormalities in drug abusers.