Interpersonal conflict among nurses (traditionally called 'horizontal violence' or 'bullying') is a significant issue confronting the nursing profession. However, there is a dearth of research focusing on horizontal violence experienced by new graduate nurses. In order to assess the priority for preventive intervention programmes, the aims of this study were to determine the prevalence of horizontal violence experienced by nurses in their first year of practice; to describe the characteristics of the most distressing incidents experienced; to determine the consequences, and measure the psychological impact, of such events; and to determine the adequacy of training received to manage horizontal violence. An anonymous survey was mailed to nurses in New Zealand who had registered in the year prior to November 2000 (n = 1169) and 551 completed questionnaires were returned (response rate 47%). Information was requested on the type and frequency of interpersonal conflict; a description of the most distressing event experienced; the consequences of the behaviour; and training to manage such events. The Impact of Event Scale was used to measure the level of distress experienced. Many new graduates experienced horizontal violence across all clinical settings. Absenteeism from work, the high number of respondents who considered leaving nursing, and scores on the Impact of Event Scale all indicated the serious impact of interpersonal conflict. Nearly half of the events described were not reported, only 12% of those who described a distressing incident received formal debriefing, and the majority of respondents had no training to manage the behaviour. First year of practice is an important confidence-building phase for nurses and yet many new graduates are exposed to horizontal violence, which may negatively impact on this process. The findings underscore a priority for the development of effective prevention programmes. Adequate reporting mechanisms and supportive services should also be readily available for those exposed to the behaviour.