Authors explored grey-matter density in 29 methamphetamine abusers and 20 healthy comparison subjects using voxel-based morphometry. Grey-matter density changes and performances on the Wisconsin Card Sorting test (WCST) were also compared between 11 short-term (<6 months) and 18 long-term (>or=6 months) abstinent methamphetamine abusers. Methamphetamine abusers had lower grey-matter density in the right middle frontal cortex (corrected p<0.05) and more total errors in the WCST (p<0.01) relative to healthy comparison subjects. Grey-matter density decrease in the right middle frontal cortex correlated with total errors in the WCST in methamphetamine abusers (r=-0.45). Long-term abstinent abusers had significantly less right middle frontal grey-matter density decrease (p<0.01) and total errors in the WCST (p<0.01) than short-term abstinent abusers, but more than the healthy comparison subjects. We report that methamphetamine abusers have prefrontal grey-matter deficit, which may, in part, recover with long-term abstinence.