This article reviews the formulation of butyl sealants for various applications. It will focus on the applications characteristics and performance properties of common butyl sealant formulations that are used in industry. Butyl rubber is an elastomeric polymer that is used in a wide variety of adhesives and sealants. In sealant formulations, butyl plays a role in the building and construction industry especially for insulting glass. Because of its unique properties it also is used in the automotive and food processing industries among others. Butyl sealants can be applied in a number of different forms. It is used widely as a hot melt sealant, preformed tape or gasket, and as a gun-dispensable sealant. Butyl rubber can be used as a primary base resin or as an additive for tack and other desired properties. This article reviews the formulation of butyl sealants for various applications.