The paper introduces the preliminary findings of the project that explores current state of affairs regarding national legislations and relevant agencies' activities with respect to investigating the child sexual abuse as a crime and combating it. The goal of the research is to map basic fields where countries might face challenges regarding the criminalization of child sexual abuse within the circle of trust and draft preliminary recommendations to enforce international activities to prevent the crime under study. The research has been conducted within the comparative paradigm framework, with the functional comparative method being the mainstream. The research included the analysis of data, provided by the official Lanzarote Committee site and Member States' replies to the items of Thematic Questionnaire on the child sexual abuse issues, in particular. The paper strives to outline trends in national legislations regarding the consideration and criminalization of illegal sexual activities with minors and child's sexual abuse. The differences and particular features in national legislations across countries are revealed regarding the concept of illegal sexual activities with the child, list of the members of the circle of trust in national laws, problems arising from varied legal age for sexual activities, national legal specifics with respect to punishment for the criminal offence under study and possible approaches to aggravating circumstances classification. Special emphasis is laid on the data collection issues.