Objectives: To investigate the relationships between food poverty and food consumption, health and life satisfaction among schoolchildren. Design: Analysis of the 2002 Health Behaviour in School-aged Children (HBSC) study, a cross-sectional survey that employs a self-completion questionnaire in a nationally representative random sample of school classrooms in the Republic of Ireland. Subjects: A total of 8424 schoolchildren (aged 10-17 years) from 176 schools, with an 83% response rate from children. Results: Food poverty was found to be similarly distributed among the three social classes (15.3% in the lower social classes, 15.9% in the middle social classes and 14.8% in the higher social classes). It was also found that schoolchildren reporting food poverty are less likely to eat fruits, vegetables and brown bread, odds ratio (OR) from 0.66 (95% confidence interval (CI) 0.45-0.87) to 0.81 (95% CI 0.63-0.99); more likely to eat crisps, fried potatoes and hamburgers, OR from 1.20 (95% CI 1.00-1.40) to 1.62 (95% CI 1.39-1.85); and more likely to miss breakfast on weekdays, OR from 1.29 (95% CI 0.33-1.59) to 1.72 (95% CI 1.50-1.95). The risk of somatic and mental symptoms is also increased, OR from 1.48 (95% CI 1.18-1.78) to 2.57 (95% CI 2.33-2.81); as are negative health perceptions, OR from 0.63 (95% CI 0.43-0.83) to 0.52 (95% CI 0.28-0.76) and measures of life dissatisfaction, OR from 1.88 (95% CI 1.64-2.12) to 2.25 (95% CI 2.05-2.45). Similar results were found for life dissatisfaction in an international comparison of 32 countries. All analyses were adjusted for age and social class. Conclusions: Food poverty in schoolchildren is not restricted to those from lower social class families, is associated with a substantial risk to physical and mental health and well-being, and requires the increased attention of policy makers and practitioners.