The article conducts a scientific and practical study of the issues of legal certainty of the "center of main interests" category in the process of determining the main proceedings in the proper consideration of cross-border bankruptcy cases. National legislation in the field of international private law, in particular, cross-border bankruptcy, and international documents in the field of cross-border insolvency are analyzed. It was found that in Ukraine, such a legal category as "center of main interests" is not normatively defined at all in the legislation, which does not ensure the implementation of the principle of legal certainty for proper application in the sphere of regulation of insolvency relations, in particular, in cross-border bankruptcy cases. However, doctrinal studies of the legal category "center of main interests" of the debtor are available. It is noted that the national legislation mentions a similar category, namely "place of main interests", which does not have legal certainty and normative consolidation, which negatively affects the existence of a unified approach to its understanding when considering cases in court. It was determined that the legal category "center of main interests" should be anchored in the relevant field of legislation of each country, taking into account internationally recognized concepts and explanations for the effective application of legal norms in cross-border bankruptcy cases. Proposals regarding clear legal certainty and regulatory consolidation of the legal category "center of main interests", which is of crucial importance for determining the main proceedings in cross-border bankruptcy cases, in national legislation, in particular, in the Code of Ukraine on Bankruptcy Procedures, for effective application in the field of regulation, have been provided insolvency relations, in particular, in cross-border bankruptcy cases, with the possibility of properly defining the main proceedings within the national jurisdiction, which will enable interested participants in the process of protecting their rights and interests within the legal systems of various jurisdictions and provide uniform approaches in understanding the legal content of the conceptual apparatus.