A typical wireless healthcare system is composed of a set of wearable or implantable sensing/interfering devices (SID’s) and a portable control station (PCS) which connects to the SID’s wirelessly. The PCS is finally connected to the hospitals, ambulances, and data centers through the wide area network(WAN). The general requirements for the wireless healthcare system are discussed. The challenges and key technologies for low power and high performance mix-mode integrated circuit design involved in the wireless healthcare system construction are presented. A chip set designed for the wireless healthcare system is introduced. Case studies are presented for continuous body temperature monitoring and continuous pH valuemonitoring with the implemented chip set.