<p>The aim of the research is to develop a model of quantum threats to the information security of blockchain ecosystems and platforms, as well as to assess their cyber resilience under cyberattacks. The research methodology includes the modeling of multi-level hierarchical blockchain ecosystems according to Mesarovich, the analysis of current quantum threats for different levels of blockchain ecosystems, the modeling of cyberattacks on blockchain ecosystems using the mathematical apparatus of Petri nets and the assessment of the resilience of blockchain ecosystems based on the probability of the system remaining operational over a given time period under quantum threats. During the research, an analysis was conducted and a brief description of a typical blockchain ecosystem was provided. A hypothesis was formulated regarding the decrease in resilience of blockchain ecosystems under the targeted cyberattacks. A model of current quantum threats to the security of national blockchain ecosystems and platforms was developed. Modeling of quantum cyberattacks on blockchain ecosystems using the mathematical apparatus of Petri nets was carried out. An assessment of the resilience of blockchain ecosystems under quantum cyberattacks confirmed the hypothesis. </p>