Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) was launched in 2008, aiming at conducting a longitudinal workup of a standardized neuroimaging, biomarker and clinico-psychological surveys. The research protocol was designed to maximize compatibility with that of US-ADNI, including structural magnetic resonance imaging analysis for the evaluation of brain atrophy, fluorodeoxyglucose and amyloid positron emission tomography, cerebrospinal fluid sampling, APOE genotyping, together with a set of clinical and psychometric tests that were prepared to achieve the highest compatibility to those used in the United States. Japanese ADNI has recruited ~357 participants (142 amnestic mild cognitive impairment, ~134 normal aged and 72 mild Alzheimer's disease (AD), as of April 15, 2010). World-wide ADNI activities will establish the rigorous quantitative descriptions of the natural course of AD in its very early stages. The data, as well as the methodologies and infrastructures, will facilitate the clinical trials of disease-modifying therapies for AD using surrogate biomarkers.