In our paper, we deal with the results of the research on Sexting and Risky Acquaintances Made by Czech Children in Cyberspace, which was implemented during 2017 by the Centre for the Prevention of Risky Virtual Communication at the Pedagogical Faculty of Palacky University in Olomouc in cooperation with the company O2 Czech Republic. The research focused on the sharing of own intimate materials in the internet environment (the so-called sexting), risky acquaintances in the online environment and other related phenomena. A total of 4878 respondents aged 8-17 (48.77% of boys, 50.41% of girls) from all over the Czech Republic participated in the research. The research Sexting and Risky Acquaintances Made by Czech Children in Cyberspace reveals a high increase in the number of children who send their own intimate materials to others in the Internet environment and who thus practise the so-called sexting. More than 15% of Czech children send their intimate materials to other persons.In our paper, we deal with the results of the research on Sexting and Risky Acquaintances Made by Czech Children in Cyberspace, which was implemented during 2017 by the Centre for the Prevention of Risky Virtual Communication at the Pedagogical Faculty of Palacky University in Olomouc in cooperation with the company O2 Czech Republic. The research focused on the sharing of own intimate materials in the internet environment (the so-called sexting), risky acquaintances in the online environment and other related phenomena. A total of 4878 respondents aged 8-17 (48.77% of boys, 50.41% of girls) from all over the Czech Republic participated in the research. The research Sexting and Risky Acquaintances Made by Czech Children in Cyberspace reveals a high increase in the number of children who send their own intimate materials to others in the Internet environment and who thus practise the so-called sexting. More than 15% of Czech children send their intimate materials to other persons.