In a population sample of 1462 middle-aged women socioeconomic data were studied in relation to obesity, assessed by a body weight index. Education, annual income, and social class were negatively correlated with weight index (WI). Husband's social class was a stronger determinant of obesity in the woman than her own class. Age of husband and number of children were significantly correlated with WI. There was also a weak correlation between being single and WI. Sick leave was not correlated to WI. Pension was correlated to WI when adjusted for age, but not when allowance was also made for social class. Age, husband's social class, education, husband's income, and number of children were independent predictors of WI among the married women. In the single women, age and own income were independent predictors of WI but not number of children, education or own social class.