Aim: This study aims to describe the adherence to the Mediterranean diet (MD), using the KIDMED questionnaire, in a sample of Catalonian adolescents and to assess the association between the MD adherence and socio-economic and lifestyle behaviours. Material and methods: Data are part of a multi-centre longitudinal study designed for the reduction of risk factors of eating and weight-related problems in adolescents. Here, a cross-sectional analysis was performed with the baseline data, academic period 2010-11. The participants were 1,502 adolescents recruited from 11 schools from the province of Barcelona. Results and conclusions: The results showed a higher level of MD adherence when parents had higher educational level, and when adolescents reported a low level of screen-time, and high weekly physical activity.