A model is formulated for the economical allocation of inspection effort in a serial production system where rejected items may be reworked, repaired, or scrapped at any production-inspection stage. After it is shown that either 100% or no inspection is optimal at each inspection opportunity, the model is restated as a mixed 0-1 linear program which may be solved by standard packages. Examples are used to show that the optimal solution is a function of whether the system``s input or output is constrained, and test problems are solved to assess the computational tractability of the proposed formulation.