Introduction. The criminal process in Ukraine is based on the basic principles of legal theories of Anglo-Saxon law. Adversarial proceedings are defined as a criminal lawsuit, on the basis of which the investigator is obliged to initiate criminal proceedings and support public prosecution. A retrospective analysis of the theoretical constructions of general theories of the criminal process in Ukraine shows their construction on the basis of Romano-Germanic provisions of continental Europe, where the basis is the publicity of the process and criminal prosecution by criminal justice authorities. In this case, the construction of general and particular theories of the process of Ukraine has a significant legal difference. Summary of the main research results. The main differences can be considered on the basis of optimization constructions, procedural economy, application of criminal repressions connected with restriction of the rights, freedoms and interests of participants of criminal proceedings. It should be noted that the current criminal procedure law does not define, to the end, the concept of general and private theories of process. Conclusions. The article offers theoretical aspects and practical solutions to emerging problems on the basis of the criminal process of Ukraine, the construction of theoretical approaches based on Anglo-Saxon law, which is important for optimizing the criminal process of Ukraine.