The design of manufacturing systems is a wide advanced area for development and application of decision making and decision support technologies. This domain is characterized by the necessity to combine the standard decision making methods with sophisticated operational research techniques and with some specific rules based on expert knowledge to take into account all principal technological constraints and criteria. A promising tendency in this area deals with the development of integrated software tools (Brown, 2004; Grieves, 2005; Stark, 2005). Their main idea consists in integrating product and manufacturing data into common database. It enables product designers to take into account the manufacturing processes constraints at early product design stage and, on the other hand, to use directly all data of product design while optimizing the corresponding manufacturing system. That's why the core of these software tools is a powerful extendable database, supported by user friendly software environment. This database can contains digital models of product and processes. In order to find an optimal manufacturing system configuration a set of advanced decision making and decision support methods are used for data processing. In this work we present the main principles and ideas of decision making in such an environment by the example of decision and support soluton for machining systems used for mass production. The used approach is based on several decision making and support techniques: powerful database of standart solutions and efficient mecanisms to search the existing elements; - expert system to choose the better solutions from database; - line balancing model based on shortest path approach; - set of problem oriented rules; - user friendly software environment. These techniques are jointly combined in the developed decision support software tool for optimal process planning, line balancing and equipement selection for optimal design of a transfer machine with rotary or mobile table.