BACKGROUND: We sought to evaluate the relationship between selected lifestyle and socio-economic characteristics and dietary habits of Greek adolescents. METHODS: During 2004, 2118 school adolescents were selected from twelve schools in Vyronas region, Athens. Dietary intake was assessed through a semi-quantitative FFQ. Principal components analysis was applied to extract dietary patterns. RESULTS: Seven components, explaining the 50% of the total variation in intake, were extracted. Component 1 ('junk food' pattern) was heavily loaded by the consumption of 'sweet' and 'salty' snacks, soft drinks and other 'fast foods'. Component 2 was characterized as 'red meat' consumption pattern. Component 3 was characterized by the consumption of vegetables, fruits and juices. Component 4 was characterized by the intake of dairy products, pasta and wholegrain bread. Component 5 can be described as rice, fish, potatoes and poultry intake. Component 6 was characterized by the consumption of 'traditional Greek cooked foods' and legumes, and component 7 was characterized by the consumption of eggs and white bread. Time spent watching television was positively associated with the 'junk food' pattern and inversely associated with the 'vegetarian/healthy' pattern. Moreover, the 'junk food' pattern was positively related to smoking status and the 'vegetarian/healthy' pattern was positively correlated with sports activities outside school. CONCLUSION: An unhealthy dietary behaviour is associated with an overall unhealthy lifestyle. Taking into account the fact that unhealthy eating habits and sedentary lifestyle have been associated with increased obesity prevalence, school- or community-based programmes should be conducted promoting healthy dietary and lifestyle behaviours.