There are no recent data on smoking habits of high-school students in Greece. The primary objective of the study was to determine the prevalence of smoking among high-school students in Northern Greece. The smoking habits of 9,276 high-school students [4,525 boys and 4,751 girls], aged between 15-18 years, in 6 cities of Northern Greece were examined. Study data were collected using a questionnaire. It was found that 32.6% of boys and 26.7% of girls are smokers. 43.3% had started smoking before the age of 14. The mean age for starting smoking was 14.4±1.9 years for the boys and 14.9±1.6 years for the girls. 25.4% of the students smoke 6 to 10 cigarettes per day and 20.7% 16 to 20 cigarettes per day. 40.2% reported that they smoke out of spite; Parents are aware that their offspring smoke in a proportion of 36.7%. Social standards and parental example were found to be the main determinants for starting smoking. The majority of the students [95.2%] stated that they are aware of the hazards associated with smoking. In conclusion, young people should be targeted with a well-planned integrated anti-smoking policy and not just an initiative for raising awareness of smoking hazards. Pneumon 2005, 18(1):99-104.