The increased availability of transgenic mouse models for studying human diseases is shifting the focus of many laboratories from in vitro to in vivo assays. The purpose of this chapter is to provide investigators with methods that will allow them to obtain well-preserved mouse brain sections to be stained with the standard histological dyes for amyloid, Congo red and thioflavin-S. These sections can as well be used for immunohistological procedures that allow detection of amyloid-ß plaques as well as pre-amyloid deposits.