This work concerns the preliminary design stage for machining systems equipped with multispindle heads, which are widely used in machining industry for high volume production. At this design stage the challenge is to find for a given part an optimal system configuration by minimizing its cost and satisfying all technological, technical and economical constraints. A number of combinatorial problems appearing at this design stage are discussed in this thesis, and in particular, the problem of configuration optimization is studied for the three following machining systems: transfer machines, machines with a mobile table and machines with a rotary table. At first, different mathematical models are suggested for each of these systems. At second, a number of optimization methods are developed for their resolution, such as algorithms for lower bounds calculation, pre-processing procedures, exact and heuristic methods and mixed approaches using several of these algorithms. On the basis of the obtained theoretical results, a prototype of decision support system for the preliminary design stage for machining systems is developed. This prototype has been successfully tested on several industrial cases.