Objective: Data from the Southampton Women's Survey have established that women of lower educational attainment have poorer quality diets than those of higher educational attainment. This relationship is strong and graded such that for every increase in level of educational qualification, there is an increase in the likelihood that a woman will have a better quality diet. It is not wholly explained by socio-economic status. Qualitative research carried out in Southampton suggests that women of lower educational attainment may have a poorer diet because they feel they lack control over the food choices they make for themselves and their families. We set out to investigate the relationship between educational attainment, perceived control and quality of diet in a sample of women from Southampton. Design: Cross-sectional study using structured interviews in which women's diet, educational attainment and perceived control were assessed. Setting: 19 Children's Centres and baby clinics in Southampton, UK. Participants: 372 women, median age 28 years. Main outcome measures: Quality of diet assessed by prudent diet score produced from principal components analysis of 20-item food frequency questionnaire, and perceived control assessed by a validated questionnaire. Results: Women of lower educational attainment tended to have lower prudent diet scores and lower perceived control scores than women of higher educational attainment. Having a lower prudent diet score was associated with consuming fewer vegetables and vegetable dishes, less wholemeal bread and vegetarian food, and more chips and roast potatoes, meat pies, Yorkshire puddings and pancakes, crisps and snacks, white bread and added sugar. In a regression model both lower educational attainment and lower perceived control were associated with lower prudent diet scores, independent of the effects of confounding factors. However there was an interaction effect such that lower perceived control was only related to prudent diet score in the group of women of lower educational attainment. Conclusion: Women of lower educational attainment perceive themselves to have less control over their lives than women of higher educational attainment, and this perceived lack of control is reflected in their diets being of poorer quality. Our findings suggest that level of perceived control over life is a more important predictor of quality of diet in women of lower educational attainment than in those of higher educational attainment. It may be that psychological and social difficulties disproportionately affect the diets of women of lower educational attainment. We are currently exploring variations in quality of diet among women of lower educational attainment in relation to a range of psychological and social factors.