Our previous study indicated that region plays a relatively small role in adolescents' health behaviour. Here, the regional patterning of health behaviour is studied further by shifting the focus to small areas. First, we test whether small area socioeconomic, demographic and housing characteristics correlate with health behaviour. The analysis then turns to the relationship between these characteristics and their individual level correlates. We wish to ascertain if behaviour is related to small area characteristics similarly for both genders and for adolescents' socioeconomic characteristics. The Adolescent Health and Lifestyle Survey data from 1989-1995 (16- and 18-year-olds, n = 1048, response rate 71%) were linked with data describing 33 subareas of Helsinki, the capital of Finland. Smoking, alcohol use, abstention from dietary fat and physical activity were used as lifestyle indicators. Gender apparently influences the extent to which the area plays a role. Logistic regression demonstrated that prolonged unemployment predicted low prevalence of abstention from dietary fat (traditional dietary patterns) among girls and heavy drinking among boys. High total rate of unemployment predicted lower physical activity among girls. Also owner-occupied housing correlated positively with girls' physical activity. Although the individual level socioeconomic characteristics were not as strongly related to health behaviour as the small area factors, a low level of education predicted smoking and alcohol use and, among girls, decreased physical activity. We conclude that small area characteristics, especially the level of unemployment of the area, may be even more strongly related to health behaviour than individual socioeconomic characteristics.