This paper provides an overview on the status, development and performance of current and future RF transistors. The targets specified in the 2005 issue and the 2006 update of the International Technology Roadmap for Semiconductors (ITRS) are addressed and used as a blueprint, and potential challenges and problems to achieve these targets are discussed. Main emphasis is given to Si-based RF transistors, i.e., Si RF MOSFETs and SiGe HBTs, but relevant information on III-V RF transistors is also included. It is shown that Si-based RIF transistors are very fast and compete successfully with GaAs pHEMTs and GaAs HBTs. As the result of a qualitative discussion, reasons for the competitive performance of Si-based RF transistors are provided. (c) 2007 Elsevier Ltd. All rights reserved.