AIMS: To investigate the associations between economic stress in childhood and adulthood, and tobacco smoking, with reference to the accumulation, critical period and social mobility hypotheses from life-course epidemiology. DESIGN/SETTING/PARTICIPANTS/MEASUREMENTS: The 2008 public health survey in Skåne, Sweden is a cross-sectional postal questionnaire study based on a random sample which yielded 28,198 participants aged 18-80 (55% participation). Logistic regression models were used to investigate associations between economic stress in childhood and adulthood, and tobacco smoking. FINDINGS: A 17.4% prevalence of men and 19.1% of women reported tobacco smoking. Tobacco smoking was more prevalent among middle-aged men and young women, among those born outside Sweden, with low occupational status, low social support, low trust, economic stress in childhood and adulthood. The accumulation hypothesis was confirmed because combined childhood and adulthood exposures to economic stress were associated (p<0.001) with tobacco smoking in a graded manner. The critical period hypothesis was not supported because the associations between economic stress in childhood as well as adulthood, respectively, and tobacco smoking were significant (p=0.004 and p<0.001) throughout the analyses. The social mobility hypothesis was confirmed because upward social mobility was significantly associated (p<0.001) with lower odds of smoking, while downward social mobility was significantly associated (p<0.001) with higher odds of smoking. CONCLUSIONS: Downward social mobility and economic stress in both childhood and adulthood should be considered as risk factors for tobacco smoking over the life course.