We compared cranial CTs of 35 habitual cocaine abusers, 16 self-reported lst-time users, and 54 headache patients using linear planimetric measures. All patients met the following criteria: age 20 to 40 years, no polydrug abuse (including alcohol), HIV seronegativity, normal albumin level, and no history of any other neurologic disease. The sex ratios and ages were not significantly different in the 3 groups. The planimetric measurements and calculated indices of cerebral atrophy were significantly different in the habitual cocaine abusers compared with the 2 other groups of patients. There were no differences between lst-time cocaine users and controls. Among the habitual cocaine abusers there was a positive correlation between the approximate duration of cocaine abuse and the calculated atrophy indices. The findings suggest that cerebral atrophy develops in chronic cocaine abusers, and the severity correlates with the duration of abuse.