Improving the product development process with new ways of describing, evaluating and selecting ideas that are built into the concept of a new product is the subject of research presented in this dissertation. The current state of research is viewed from three aspects: product development, ideas' life cycle, and evaluation and selection of ideas. A systematic review of recent literature gives a theoretical view of the area of research especially with regard to the product development process, possibilities of description, evaluation and comparison of ideas, defining of attributes for the qualitative and quantitative evaluation of ideas and methods for decision support in the ideas' selection process. The review of the status of idea management in the economy is given by the results of the survey which included firms that have mechanical products with their own development in their production line. Data processing found when and how the collection of ideas is performed, which motives and needs are triggers for the collection of ideas, how the companies are organized and trained, and how they conduct the assessment, evaluation and selection of ideas. An integral part of the survey was the evaluation of attributes and criteria for evaluating the value of an idea by surveyed companies. The resulting findings were used to describe a detailed model for data collection, analysis and the qualitative and quantitative evaluation of ideas. The conducted survey revealed the attributes for idea analysis, the criteria for assessment and methods for the evaluation and selection of ideas, which ultimately resulted in the proposed methodology for evaluating ideas and methodology for the selection of ideas for product development. In the process of verification, the applicability of the proposed methodologies was evaluated on two examples. In this process a larger number of assessors were used and the results obtained using two different methods were compared and correlated. The dissertation ends with a discussion on the conducted research and the results obtained in accordance with set targets. The results presented in this dissertation were obtained together with theoretical implications on the field of product development. They present prominent contributions to knowledge of product development, together with suggestions and directions for future research.