Numerous studies have documented cognitive impairments and hypoactivity in the prefrontal and anterior cingulate cortices in drug users. However, the relationships between opiate dependence and brain structure changes in heroin users are largely unknown. In the present study, we measured the density of gray matter (DGM) with voxel-based morphometry in 30 lifetime heroin-dependent individuals who had abstained from drug use for 5 months, and 34 healthy participants. The DGM of the prefrontal, temporal and cingulate cortices significantly decreased in heroin addicts relative to the healthy group. Critically, partial correlation analysis, which controlled for age, education and gender factors as well as nicotine use and heroin abstinence duration, showed that the duration of heroin use negatively correlated with the DGM in heroin-dependent individuals. These results provide compelling evidence for structural abnormality in heroin-dependent individuals and further suggest that duration of heroin use is a critical factor leading to brain damage. (Contains 3 tables and 1 figure.)