Health barometers are surveys of the opinions, knowledge, attitudes, and behaviors of the French population. In this first youth health barometer, 4,115 young people aged 12 to 19—both in school and out of school—were surveyed. Data collection was conducted in participants’ homes using the CATI (Computer-Assisted Telephone Interviewing) system. A pilot survey was used to finalize and validate the questionnaire. A total of 150 questions were grouped into different themes with the aim of exploring the epidemiological aspects of health behaviors and the psychosocial aspects of attitudes and health determinants. The most sensitive questions (illicit drugs, suicide, sexual violence, sexuality) were asked only of 15- to 19-year-olds. The young people willingly participated in the telephone interview; the refusal rate was significantly lower than in the adult survey. The analysis of the results focuses on bivariate statistics; the authors emphasize that a significant correlation does not imply a causal relationship. A few explanatory variables were used: these include sociodemographic variables and variables describing health behaviors.