ASSOCIATION OF LONELINESS, IMPULSIVITY AND ALCOHOL USE WITH  SUICIDAL BEHAVIOR IN ADOLESCENTS Background: Suicide and suicide attempts are public health problems. Their prevention requires the detection of predictor factors. Aim: To determine the predictive value of loneliness, impulsivity and alcohol use on suicidal behavior in adolescents. Subjects and methods: Suicidal behavior, Loneliness (UCLA), Impulsivity (Barratt) scales  and the Alcohol Use Disorders Identification Test (AUDIT), were applied to 763  high school students aged 14 to 19 years (49% males), living in  Chillán, Chile. Results: Nineteen percent of participants had attempted suicide and 34.3% had suicidal ideation. Loneliness, impulsivity and alcohol use were directly related to suicidal behavior. These predictors explained 31% of the suicidal behavior. The most important risk factor is loneliness, followed by female gender, impulsivity and alcohol use. Conclusions: Loneliness, impulsivity and alcohol use are risk factors for suicide among adolescents. Women are at higher risk than men.