Modern approaches to the organization of complex technical systems overhaul make managers and companies face a task of rationalizing the organization of overhaul maintenance functions for the purpose of shortening the cycle itself, cutting down the time and energy per unit of time, as well reducing the total costs in general. Experiences from the practice show frequent delays in the fulfillment of the obligation towards the end customer, i.e. the fulfillment of the obligation by the unplanned engagement of additional work at increased costs. During project planning and management, managers are facing several important questions and two are particularly emphasized – what is duration of the project and what are the project costs? It is extremely difficult to give an adequate answer to each of stated questions, particularly for projects of non-repeating character. Such projects often include new activities, which increases the level of uncertainty and risk. It is difficult to predict all of problems that may arise during the project implementation as well as what impact it will have on the development of the entire business system. The research conducted in this doctoral thesis has been focused on the analysis of possibilities of applying multi-criteria decision making and various optimization methods in analysis of complex technical systems overhauling (at the level of overhaul managing, planning and monitoring) as well as possibilities to investigate as well as to achieve the optimal solution of the plan in terms of both cost and time framework according to predetermined multi-criteria goal function. Due to the constraints of single-criteria decision-making systems that included optimization of one criterion (which is very rare in practice) their application was limited as well as solutions obtained. In this doctoral thesis one analyzes the possibility of applying multi-criteria decision making using different optimization methods in the analysis of complex technical systems (by applying it at the level of overhaul management, planning and monitoring) as well as the ability to achieve various versions of suboptimal solutions in terms of cost and time according to the given criteria. By reviewing the existing models of managing, planning and monitoring of complex technical systems overhaul, analyzing the existing models stated in the relevant academic literatures, previous researches and long-term personal experience in the field, it has been concluded that there is a space for suggesting the improvement and model development of planning and monitoring of complex technical systems overhaul by applying as well as modifying various methods and techniques (CPM, PERT / COST and linear programming technique). Suggested multi-criteria model has been tested on the selected complex technical system (a construction machine). However, this does not mean that the model cannot be applied to any other complex technical system. For the purpose of confirming set hypothesis, the time analysis of the CPM method with the estimated duration of activity as deterministic size and the PERT method with the estimated time periods of activity as stochastic sizes were performed. By investing additional costs on the shortening of the duration of each activity, where the technological possibilities allow it, the project optimization by PERT / COST method and the linear programming method according to the time and cost of the project was carried out. The set optimization model is allowing a choice between more versions of time-cost sub-optimal solutions as well as a probability calculation of completing a project related to the original time estimated. One can expect that this research can be applied to other projects - especially to those which are of non-repeating character.