The article touches upon a set of issues related to the cross-border crime definition and features. Cross-border crime can be defined as a criminal-legal, criminological and criminalist concept. The author’s approach is that it is exactly criminal-legal dimension of this problem that is primary one. A criminal-legal understanding of cross-border crimes is suggested. It is analyzed by comparing the provisions of a number of international and national acts in the context of cross-boundary as a legal concept and characteristics of offences. There is emphasized that cross-border crimes constitute a relatively stable set of crimes that threaten the interests of states in the sphere of border and national security. The cross-border crimes objective features are considered. They include public interests, offender’s modus operandi, the victim, items transferred across the border. It is concluded that the cross-boundary nature in the criminal law of Ukraine stems from the peculiarities of the offender’s actions. The classification of crimes into unconditionally and conditionally cross-border is suggested. Such a division is associated with the obligatory/optional nature of such an objective feature as border crossing.