OBJECTIVE: Deficits in dopaminergic function may contribute to hypertrophy of striatal structures associated with typical neuroleptic treatment. In light of a body of research that has associated chronic cocaine use with extrapyramidal symptoms and striatal dopaminergic depletion, the authors looked for evidence of striatal dysmorphology in patients with chronic cocaine dependence. METHOD: Caudate, putamen, and total brain volumes were quantified by means of magnetic resonance imaging in 25 cocaine-dependent and 20 healthy subjects. RESULTS: Normalized caudate and putamen volumes were 3.40% and 9.18% larger, respectively, in the cocaine-dependent subjects. CONCLUSIONS: These observations suggest that deficits in dopaminergic function associated with cocaine dependence may contribute to striatal hypertrophy.