a b s t r a c tBackground: Driving under the influence of alcohol and drugs has been identified as a risk factor for road traffic crashes. We have assessed the prevalence and predictor factors for driving after alcohol and drug use by adolescents. Methods: A cross-sectional survey involving 11,239 students aged 14-18 years from 252 private and public schools in the Valencia region of Spain was conducted. The prevalence and predictors of driving after alcohol use, alcohol and drug use, or drug use during the previous 6 months were measured. Results: Of the students who reported driving (20%), 45.1% indicated driving after alcohol and drug use. The consumption of various drugs was higher among students who drove a vehicle compared with those who did not. The likelihood of driving after consuming alcohol, or alcohol and drugs, increased in line with the number of standard drink units per week, reports of any lifetime alcohol-or drug-related problems, and poor family relationship. In addition, masculine gender and early alcohol use increased the likelihood of driving after consuming alcohol. Conclusions: Driving after alcohol and drug use is quite prevalent among adolescents in the Valencia region of Spain. There is a need for implementation of targeted policies for adolescents. This should focus on education and information on alcohol/drug use and driving.