111 most of the studies on tool management, lot sizes are taken as pi'edetermined input while deciding on tool allocations and machining |)arameters. In this study, we considered the integration of lot sizing and tool rnaricigement problems for single and multi i:>eriod cases. For the single period case, we proposed a new algorithm. By this algorithm we not only improved the overall solution by exploiting interactions, but also prevented any infeasibility that might occur lor the tool management problem due to the decisions made at the lot sizing level. The computational experiments showed that in a set of randomly generated problems 22.5% of solutions found by a. traditional approach were infeasible and the proposed joint approach improved the overall solution by 6.8%. For the multi period case, we proposed live new algorithms. Among these algorithms, the most promising one was tlie Look Atiea.d-LUC algorithm, which improved the overall solution on the average by 6.5% compared to the best known algorithm, Wa.gner-Whitin, used in traditional approcich, over a set of randomly generated problems.