How to regenerate the waterfront environment for the high quality urban spaces accessible for pedestrians? This is one of the key research issues of the dissertation thesis Waterfront Regeneration- the example of the City of Trenčín. The primary objective of this work is to find the strategic framework for the complex waterfront regeneration. While fulfilling this goal, we focus our attention and narrow the range of the research to the case study of the Central city core area- Trenčín. Wider problem structuring divides the study into three research levels (theoretical, practical and experimental). We map the global regeneration examples in theoretical way and use the methodology of analysis and synthesis, which is amended by Research by Design and Research by Action methodology in practice. The experimental research generates a new method of the participatory planning- Urban walk, which maps the activities in the waterfront public areas. We participate in the long term process of the Central city core waterfront regeneration as a result of collaboration between the local municipality and the Faculty of Architecture SUT Bratislava. The participatory research line of the project Trenčín is You comprises the integral part of the regeneration process. Project maps the essential requirements of the public, communities and experts on the interdisciplinary level. The initiation of the multilayer participation is the main project result. As a core project team member, we participate by finding the project strategy and generating the competition brief (existing and new waterfront regeneration tools and objectives). We also evaluate the results of the international urban design competition Trenčín - City on the River. Based on our research findings, we define the problematic aspects of the waterfront regeneration. They illustrate the current status of the Central city core area and map the impact of the competition results on the urban structure and waterfront area. We generalize our statements in the discussion and we propose the knowledge application possibilities in different areas.