The relationship between obesity and mental health was investigated, using data obtained from 1,660 persons selected as representative of 110,000 inhabitants of a residential area of New York City. In addition to confirming the previously noted relationship between obesity and age, preliminary analysis revealed a striking relationship between obesity and socioeconomic status of origin. The prevalence of obesity was 7 times higher among women reared in the lowest social class category as compared with those reared in the highest category. Scores made by the obese respondents on 9 mental health indices were compared with scores made by individuals of average weight. The obese respondents made more pathological scores on 8 of the 9 measures and on 3 of these the difference was statistically significant ("immaturity," "rigidity," and "suspiciousness").