Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common cause of dementia in the elderly. Magnetic resonance (MR) or computed tomography (CT) imaging is recommended for routine evaluation of dementias. The development of molecular imaging agents and the new techniques of MR for AD are critically important for early diagnosis, neuropathogenesis studies and assessing treatment efficacy in AD. Neuroimaging using nuclear medicine techniques such as SPECT, PET and MR spectroscopy has the potential to characterize the biomarkers for Alzheimer's disease. The present review summarizes the results of radionuclide imaging and MR imaging in AD.