Background: Childhood behavior problems are associated with premature mortality. To identify plausible pathways that may account for this association, we explored the extent to which childhood behavior problems relate to health behaviors and health outcomes at midlife. Methods: The Aberdeen Children of the 1950s (ACONF) study comprises 12,500 children from the Aberdeen area, Scotland, UK. Childhood behavior problems were assessed by teacher ratings at children's age of 6-12 years. Between 2001 and 2003, surviving study members, then aged 46-51 years, were mailed a questionnaire containing enquiries about physician-diagnosed conditions (long-term disease, diabetes, high blood pressure), general health, well-being, weight, smoking, and alcohol intake. A total of 7,183 responded. Results: Two dimensions of externalizing (conduct problems and hyperactivity) and one of internalizing (emotional problems) behaviors were associated with adult health. Childhood conduct problems were related to an increased risk of long-term disease (odds ratio per one standard deviation increase; 95% confidence interval: 1.15; 1.02-1.29 for men; 1.26; 1.08-1.47 for women), obesity (1.16; 1.01-1.33 in men; 1.38; 1.14-1.68 in women), cigarette smoking (1.20; 1.07-1.34 in men; 1.17; 1.01-1.35 in women), and lower well-being. Childhood hyperactivity was associated with earlier initiation of smoking in men and women; smoking more cigarettes in women; and binge-drinking, as well as a higher frequency of hangovers in men. Internalizing behavior was related to a reduced the risk of ever smoking (0.87; 0.80-0.95 in men; 0.92; 0.85-0.99 in women) and to healthier drinking patterns. In women but not men, internalizing problems also predicted a later age of smoking onset. Adjusting for socio-economic status of origin, childhood intelligence, education and age had negligible effects on these results. Conclusions: Childhood behavior problems were associated with a series of adult health-related habits that may partially account for the link between early problem behaviors and premature mortality.