The design, construction and test of a thin (200 win overall substrate thickness), large area (10 cmX10 cm) microstrip gaschamber(MSGC)with both strip and pad readout is described. Thedevice is built on a 6m. silicon wafer. Thecharacteristics ofthis detector makeit suitable as a building block of a tracking system at LHC/SSC1. IntroductionSince its introduction [1,2], themicrostrip gascham-ber has been considered one of the most promisingdetectors for the instrumentation of the next genera-tion of experiments at high luminosity machines [3,4].This is due to very good detector performance, nowvery close to those of a solid state microstrip detector,as well as to its simplicity, low-cost and radiationresistance (intrinsic to a flushed detector with internalgas gain). Because of these features, this detector wasquite early successfully used to track particles in twofixed target experimentsat CERN,NA12[5] and RD22[6], clearly showing that it is already a useful instru-ment forpresent dayphysics.Moving from fixed target medium scale experi-ments, having at most thousands of channels, to hugecollider experiments at LHC/SSC with millions ofreadout channels is, obviously, a large step forward.Nevertheless, almost all the experiments which havebeen proposedfor both LHCand SSCinclude the useof MSGCsin thetracking system [7,8]. Commonto allthese proposals is the needfor MSGCswith:i) the largest possible area (typically 100CMZ) com-patible with low occupancy to reduce the number