In this chapter, the chiplet design and heterogeneous integration packaging are presented. The origin of chiplets, 5 different chiplet designs and heterogeneous integration packaging and their advantages and disadvantages will be briefly mentioned first. It is followed by the communications (bridges) between chiplets with various configurations. Specially, the bridges embedded in build-up package substrates and bridge embed in fan-out epoxy molding compound are mentioned. Finally, a hybrid bonding bridge will be provided.