In the contemporary world of science and practice, the landscape architecture's area of expertise includes increasingly complex tasks related to the city management, renewal and development. City planners, urban and landscape researchers agree on a number of emerging interdisciplinary issues, as the city is a multifunctional organism undoubtedly having human well-being needs as its centrepiece. Dissertation deals with the topic of interaction between landscape architecture and urbanism. The research seeks to answer how landscape architecture can be beneficial in pursuit for the sustainable coexistence of nature and the city, what forms the creative field of landscape architecture in the urban environment and what determines the optimal expression of landscape architectural means in the urban landscape. The aim of the research is to reveal the development and role of landscape architecture in the city, to develop a methodological model for optimizing interaction between landscape architecture and urbanism solutions. The dissertation consists of the introduction, three chapters, general conclusions, list of references, and annexes. The introduction introduces the problem analysed in the dissertation, its relevance, the object of research, work methods, novelty, and statements of defence and structure of work. The first chapter discusses the evolution of the concept of landscape architecture, the field of professional activity of landscape architecture, and the expression of landscape architecture in the urbanism processes of the 19th to the 21st centuries, analyzes and summarizes the aspects of research on the interac-tion of landscape and urbanism, as well as methods of urban environmental research. The second chapter creates the framework of the interaction between the solutions of landscape architecture and urbanism. The solutions of the general plans in the aspect of landscape architecture are explored. The dissertation contains examination and analysis of the opinion of experts from Lithuania and abroad on the role of landscape architecture in the development of the city. The model of the analysis of interaction between landscape architecture and urbanism solutions is compiled: establishing the main principles of optimal interaction, preparing a three-dimensional system of test criteria based on the principles of sustainability and ecological ethics. The third chapter presents a methodical model for optimizing the interaction of landscape architecture and urbanism solutions, in which the results of the interaction research are interpreted and con-ceptualized using landscape architecture methods. A total of five articles were published in peer-reviewed scientific journals and three in in other peer-reviewed publications on the topic of the dissertation. In addition, six presentations and one poster presentation on the subject of the dissertation were presented at the scientific conferences of Lithuania and other countries.