A common, high level means to describe component and system behavior, define specifications and exchange data is needed to complement the microwave/mm-wave monolithic integrated circuits (MMIC) program. A new DARPA funded Phase 3 effort is underway to develop a MMIC hardware description language (MHDL) to satisfy this need. The development of MHDL is key to establishing microwave analog hardware specification and description capabilities that complement the digitally-oriented VHSIC hardware description language (VHDL).