The use of queuing software in manufacturing has been limited but is now growing rapidly. The application of queuing analysis to manufacturing is based on queuing network theory, which began in the 1950s. For 20 years the computer-communications community made most of the advances and applications. In the 1970s, researchers found applications to a class of automated systems called flexible manufacturing systems. They demonstrated the advantages of queuing analysis over other techniques, but the use of queuing models in manufacturing remained limited. The 1980s brought new solutions for the models based on node-decomposition methods. A shift in manufacturing strategy from cost reduction to lead-time reduction boosted the applicability of queuing models: the theory allowed analysis of more general systems, and the waiting time analysis was central to lead-time reduction. Queuing software is now used by industrial analysts, managers, and educators. Close contact between researchers and industrial users has been critical to the growth in use of the software. Emphasis on such contact, along with better linkages to operational systems, will ensure continued growth of manufacturing applications of queuing software.