Context: Cushing's syndrome (CS) affects cognition and memory. Objective: Our objective was to evaluate memory and hippocampal volumes (HV) on 3-tesla magnetic resonance imaging (3T MRI) in CS patients and controls. Patients and Methods: Thirty-three CS patients (11 active, 22 cured) and 34 controls matched for age, sex, and education underwent Rey Auditory Verbal Learning Test and Rey-Osterrieth Complex Figure memory tests. Gray matter and HV were calculated on 3T MRI, using FreeSurfer image analyses software. Results: No differences in HV were observed between active and cured CS or controls. Memory performance was worse in CS patients than controls (P < 0.04 in active; P < 0.03 in cured CS) but did not differ among CS groups, which were therefore analyzed together; they performed worse for verbal (P = 0.02) and visual memory (P = 0.04) than controls. In 12 CS patients, memory was below normative cutoff values for verbal (n = 6, cured), visual memory (n = 10, six cured) or both (n = 4); these patients with severe memory impairments showed smaller HV compared with their matched controls (P = 0.02 with verbal impairment; P = 0.03 with visual impairment). They were older (P = 0.04), had shorter education (P = 0.02), and showed a trend toward longer duration of hypercortisolism (P = 0.07) than the remaining CS patients. Total (P = 0.004) and cortical (P = 0.03) brain gray matter volumes were decreased in CS compared with controls, indicating brain atrophy, whereas subcortical gray matter (which includes HV) was reduced only in the 12 patients with severe memory impairment. Conclusion: Verbal and visual memory is worse in CS patients than controls, even after biochemical cure. HV was decreased only in those whose memory scores were below normative cutoff values. Copyright © 2012 by The Endocrine Society.