In this paper, several techniques for designing asynchronous circuits in Gallium Arsenide are presented. Several new circuits were designed, to implement specific functions necessary to the design of a full microprocessor. A sense-amplifier, a completion tree, and a general circuit structure for operators specified by production rules are introduced. These circuit were used and tested in a variety of designs, including two asynchronous microprocessors and two asynchronous static RAM's. One of the microprocessor runs at over 100 MIPS with a power consumption of 2 Watts.