Miniature analytical instruments that operate in a rarified gas environment will require vacuum pumping systems that are of suitable performance, size, weight, and power consumption. A subset of these analytical instruments will require throughput pumping systems, that is systems that exhaust pumped gas to the external environment rather than capturing it. Vacuum pumps are available in both capture and throughput configurations. Most "normal" sized gas analytical systems in use today are equipped with throughput pumping systems because of sampling and total mass flow requirements. This talk will describe existing pumps and efforts to miniaturize them. Performance and design criteria will be explored focusing on creating specifications based on overall system requirements. Problems with shrinking existing designs as well as several novel designs will be considered. Some new microfabrication processes will be described with an eye towards techniques that will be helpful in the fabrication of miniature vacuum pumping systems. *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.