When considering gas compressor stations for pipeline projects, the economic success of the entire operation depends to a significant extent on the operation of the compressors involved. In this paper, the basic factors contributing to the economics are outlined, with particular emphasis on the interaction between the pipeline and the compressor station. Typical scenarios are described, highlighting the fact that pipeline operation has to take into account variations in load. The second part of the paper is used to address the control and operation of centrifugal compressors in pipeline service. This includes a description of the interaction between the compressor and the piping system, and methods to influence the operating point of the compressor. Steady state and transient operation is considered. Based on the demand profile, the optimization of equipment under fluctuating pipeline demand is discussed, and the importance of sizing the driver, and selecting the best number of drivers, is stressed.