The relevance of the subject of study is due to the practical importance of protecting critical infrastructure facilities in the context of increasing potential threats from criminal encroachments associated with the illegal privatisation of such facilities. The purpose of the study is to analyse the current state of criminal legal protection of critical infrastructure from illegal privatisation, develop separate recommendations on the specifics of organising an investigation into the illegal privatisation of critical infrastructure objects, and provide proposals for improving the national system for protecting critical infrastructure from illegal privatisation. The methodological approach to the study was based on using a diagnostic method, by which privatisation is considered both as a social and legal phenomenon. Methods of analysis, dogmatic, formal-legal, modelling, comparative-legal are also used. The study provided for a comprehensive review and examination of the current state of regulatory regulation of the protection of critical infrastructure facilities from illegal privatisation in the criminal legal dimension. It is established that in Ukraine, it is insufficient and needs to be improved. Proposals on criteria for assigning critical infrastructure objects to privatisation processes, creating legal mechanisms for their alienation into private ownership and ensuring proper state control over their further functioning are substantiated. The study focuses on the specifics of starting a pre-trial investigation of the illegal privatisation of critical infrastructure facilities and organising a pre-trial investigation, considering the forensic classification of criminal offences committed during the privatisation process. It is proposed to supplement Article 233 of the Law of Ukraine on criminal liability with a separate qualification composition, which would establish criminal liability for the illegal privatisation of critical infrastructure facilities, providing for the commission of this socially dangerous act of punishment in the form of imprisonment. The results obtained are of practical importance in the development and substantiation of theoretical provisions, conclusions and recommendations for improving the national system for protecting critical infrastructure from criminal offences