The aim of the article. The aim of the article is to study the Ukrainian ecosystem of startups and highlight the determinants and challenges of marketing management of the national IT startup industry in modern conditions. The results of the analysis. It was revealed that in the conditions of increasing entropy at all levels of social systems, the development of the start-up industry becomes critical for adapting to external turbulences. The prerequisites and prospects for the development of the ecosystem of IT startups in Ukraine were analyzed. It is emphasized that the priorities of managing the national economy should shift in the direction of finding opportunities for active formation and use of the country's intellectual potential on the basis of effective marketing management of the start-up industry. The critical determinants of modern IT start-ups have been identified: the issue of choosing forms, methods and tools for marketing management of innovative projects The modern management challenges of the IT startup industry in Ukraine have been identified: insufficient financing at all stages and stages of the startup and requirements for transformation of sources of investment income; breaks in logistics chains with partners and suppliers; requirements of anti-crisis marketing and low-budget flexible PR; aggravation of the need for institutional support and legal support; relocation and optimization of project teams; adaptation of a client-oriented strategy to the turbulence of client needs; personnel management in conditions of shortage of personnel and lack of qualifications. The problems of transformation of target markets, relocation of teams, investment and support of financial sustainability of Ukrainian IT startups were considered. As a solution, it is proposed to use the tools of adaptive marketing management, correction of business models, the use of innovative sources of investment and personnel management. The role of IT startups as a catalyst of innovative transformations and digital transformations of all sectors of the country's economy, the basis for ensuring economic growth, is emphasized. The importance of ensuring an effective system of adaptive marketing management of IT startups as a driver of accelerated innovative development and national security of Ukraine is substantiated. Conclusions and direction for further research. IT startup is a company with a necessarily innovative component, which operates in conditions of extreme uncertainty and limited resources and is in search of a sustainable and scalable business model. That is why it is IT startups that have the role of leader and catalyst of social development in the digital economy. In order to find exactly the right sustainable and scalable business model, IT startups need effective marketing management, since the creation of a business model includes the implementation of marketing management tasks, namely: defining segments, product development, value proposition , sales channels, pricing, etc. The Ukrainian IT startup industry has a strong potential for development and should be considered as a driver of accelerating progress. In wartime conditions, the national IT startup industry is characterized by the relocation of teams, partial disintegration of teams, remote work, efforts of startups to help the country with their innovative solutions, the main focus on domestic and European markets. During this period of time, Ukrainian IT startups also faced many challenges such as: financial and investment, personnel and qualification, marketing and legal. Solving these problematic issues and challenges of marketing management of IT startups will be facilitated by iterative analysis and operational correction of business models for effective management of the marketing strategy in terms of finding new target markets, revising the value proposition, adjusting the marketing mix, as well as expanding the use of innovative sources of investment, intensifying participation international organizations, hiring and training new employees with less work experience.