AbstractThis paper is concerned with analytical determination of the mean and standard deviation of the job flow-time in a job shop in which the F.C.F.S. dispatching rule is in use. A hypothetical job shop is constructed to generate simulation results for comparison with the analytical results. Consistency of the results reveals the validity of the analytical model. It is also shown that the model is quite robust at a low level of shop load. So the model can be applied to analyze certain types of actual shops.