Numerous clinical studies suggest a link between elevated cholesterol and increased risk of Alzheimer disease (AD), and the preponderance of data suggests that statin therapy may reduce the risk of AD later in life. The first clinical investigation of statin therapy in patients with AD, the AD Cholesterol-Lowering Treatment (ADCLT) trial, found that atorvastatin 80 mg/day was associated with improvements relative to placebo on some, but not all, cognitive measures after 6 months and 1 year of therapy. We report here findings from a pilot ADCLT substudy showing a nonsignificant reduction in total hippocampal volume with 1 year of atorvastatin therapy compared with placebo, driven by a highly significant reduction in right hippocampal volume with atorvastatin therapy.