The uses of blocked polyisocyanates in automotive coatings and sealants has progressed rapidly in the recent past in both the European and American markets. The use of blocked polyisocyanates with polyols provide the performance advantages of a two component system with the simplicity of a one component system. In addition, one component systems based on blocked polyisocyanates have an extended pot life. This paper summarizes the chemistry and applications of blocked polyisocyanate technology. A review of polyisocyanate types and blocking agents and description of the automotive applications for sealants, primers and top coats is made.