This article provides 12-month prevalence rates of youth exposure to websites which encourage self-harm or suicide and examines whether such exposure is related to thoughts of self-harm and thoughts of suicide in the past 30 days. Data were collected via telephone from a nationally representative survey of 1560 Internet-using youth, ages 10-17 residing in the United States. One percent (95% CI: 0.5%, 1.5%) of youth reported visiting a website that encouraged self-harm or suicide. Youth who visited such websites were seven times more likely to say they had thought about killing themselves; and 11 times more likely to think about hurting themselves, even after adjusting for several known risk factors for thoughts of self-harm and thoughts of suicide. Given that youth thinking about self-harm and suicide are more likely to visit these sites, they may represent an opportunity for identification of youth in need of crisis intervention. (C) 2014 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.