Alzheimer's disease (AD) is the most common form of dementia and is characterized by progressive cognitive decline and memory loss. One of pathological hallmarks of AD is the accumulation and deposition of β-amyloid (Aβ) plaques which is a potential target for the early diagnosis of AD. Positron emission tomography (PET), a sensitive radionuclide imaging technique, has provided opportunities to detect Aβ plaques of AD. PET-imaging probes of Aβ plaques have been extensively developed during the last decade. [(18)F]Florbetapir, the (18)F-labeled PET-imaging probe of Aβ plaques, was recently approved by US Food and Drug Administration. A number of follow-on PET-imaging probes are currently being developed in academia and pharmaceutical companies. This article will discuss the recent development of PET-imaging probes from [(11)C]PIB to [(18)F]Florbetapir, which are in clinic trials, and several follow-on probes in preclinical stage.