Growing evidence on importance of the flow of man-made products in causing indoor and outdoor pollution urges to minimise the content and the leaching of the hazardous substances from products. Ecodesign, which integrates life cycle related environmental aspects into product development could be used to minimise potential adverse impact caused by hazardous substances. Review of the existing ecodesign methods highlighted the weakness in identifying and assessing health related and environmental impacts of hazardous substances contained in products, especially with regard to exposure assessment. Therefore, a new semi-quantitative ecodesign method applicable for different types of products has been developed. The application of the new ecodesign method includes the ranking of the most severe chemical hazards by using chemicals classification according to Globally Harmonised System, combined with exposure ranking following the principles of chemicals risk assessment. The application of the method is demonstrated with a case study on different products. The method allows eco-designer to identify needs for and elaborate eco-design proposals, and promotes communication and information exchange through the supply chain. The goal of the research was to develop an eco-design method to reduce the adverse effects of harmful chemical substances on the environment and human health during the product life cycle. To reach the objective it was necessary to perform the following tasks: 1) develop a criteria system for evaluation of materials and elaboration of ecodesign proposals, considering the properties of the toxic substances, re-use and recovery opportunities, design parameters and product life cycle, 2) develop principles for verification of the information on hazardous substances delivered by up-stream suppliers to enable collection of reliable information, 3) validate the eco-design method with the help of case studies showing application of the method and feasibility for information collection via supply chain. Volume and structure of the thesis: the work consists of the introduction, four sections, conclusions and Annex. It includes 132 pages, including 39 figures, 41 table and a bibliography with 249 sources. The main scientific novelty of the thesis: a new semi- quantitative eco-design method to reduce impacts of toxic releaases from products and improve material efficiency. The main scientific novelty of this method: 1) bridging the needs of product development for quick, resource saving decision making with scientific chemicals risks assessment principles, 2) ranking system to evaluate chemical hazards based on chemicals classification, exposure by releases of chemical substances from products, and recycling patterns of the materials in order to enable generation and evaluation of eco-design proposals leading to better protection of the man and consumers, and resources. This work has been supported by the European Social Fund within the project “Support for the implementation of doctoral studies at Riga Technical University”