ABSTRACT This paper describes a C-language software system dubbed FIDOS (Field Development Optimization System) that optimizes development and production from one or more gas reservoirs producing through one or more compressor stations. The optimal schedule delivers the economic portion of a requested profile of offtake rate plus spare capacity vs time over a specified planning horizon. In order to base selection of wells or HP increments upon incremental NPV and PVR, a reservoir simulator and an economic evaluator are imbedded in FIDOS. To reduce computing time for the many simulations, the nodal analysis equations that determine deliverability are solved with a specially tailored technique. With more than one compressor station a generalized network flow model is used it-eratively to determine optimal capacity and production at each station. To preserve machine independence Postscript is used to generate mixed graphical/numerical presentations of inputs and results. An example illustrates FIDOS' utility.