This paper presents a new hybrid optimization approach based on immune algorithm and hill climbing local search algorithm. The put-pose of the present research is to develop a new optimization approach for solving design and manufacturing optimization problems. This research is the first application of immune algorithm to the optimization of machining parameters in the literature. In order to evaluate the proposed optimization approach, single objective test problem, multi-objective 1-beam and machine-tool optimization problems taken from the literature are solved. Finally, the hybrid approach is applied to a case study for milling operations to show its effectiveness in machining operations. The results of the hybrid approach for the case Study are compared with those of genetic algorithm, the feasible direction method and handbook recommendation. (c) 2007 Elsevier Ltd. All rights reserved.