OBJECTIVE: We sought to identify the characteristics of youth who are targets of Internet harassment and characteristics related to reporting distress as a result of the incident. PARTICIPANTS AND METHODS: The Second Youth Internet Safety Survey is a national telephone survey of a random sample of 1500 Internet users between the ages of 10 and 17 years conducted between March and June 2005. Participants had used the Internet at least once a month for the previous 6 months. RESULTS: Nine percent of the youth who used the Internet were targets of online harassment in the previous year. Thirty-two percent of the targets reported chronic harassment (ie, harassment > or = 3 times in the previous year). In specific incidents, almost half (45%) knew the harasser in person before the incident. Half of the harassers (50%) were reportedly male, and half (51%) were adolescents. One in 4 targets reported an aggressive offline contact (eg, the harasser telephoned, came to the youth's home, or sent gifts); 2 in 3 disclosed the incident to another person. Among otherwise similar youth, the odds of being a target of Internet harassment were higher for those youth who harassed others online, reported borderline/clinically significant social problems, and were victimized in other contexts. Likewise, using the Internet for instant messaging, blogging, and chat room use each elevated the odds of being a target of Internet harassment versus those who did not engage in these online activities. All other demographic, Internet-use, and psychosocial characteristics were not related to reports of online harassment. Thirty-eight percent of the harassed youth reported distress as a result of the incident. Those who were targeted by adults, asked to send a picture of themselves, received an aggressive offline contact (eg, the harasser telephoned or came to the youth's home), and were preadolescents were each significantly more likely to report distress because of the experience. Conversely, the youth who visited chat rooms were significantly less likely to be distressed by the harassment. CONCLUSIONS: Internet harassment can be a serious event for some youth. Because there has been a significant increase in the prevalence of Internet harassment from 2000 to 2005, adolescent health professionals should continue to be vigilant about such experiences in the lives of young people with whom they interact. Social problems and online aggressive behavior are each associated with elevated odds of being the target of harassment. Thus, prevention efforts may be best aimed at improving the interpersonal skills of young people who choose to communicate with others using these online tools. Adolescent health professionals should be especially aware of events that include aggressive offline contacts by adult harassers or asking the child or adolescent to send a picture of themselves, because each of these scenarios increase the odds of reporting distress by more than threefold. Findings further support the call for the inclusion of Internet-harassment prevention in conventional antibullying programs empowering schools to address Internet bullying situations that occur between students. This will not solve all situations, however. We also must encourage Internet service providers to partner with consumers to be proactive in serious harassment episodes that violate criminal laws and service-provider codes of conduct.