This study evaluated the quality of diet of the population receiving the Bolsa Familia Program in Curitiba, state of Parana, Brazil. It was a population-based cross-sectional study, conducted from July 2006 to July 2007. 747 beneficiaries were interviewed from 19 years of age, of both genders. A 24 hour-recall was implemented in order to assess the quality of the diet and the Healthy Eating Index (HEI) was used as a parameter for the classification of the group in consumption levels. Descriptive statistics were used to describe the diet quality of the studied population. Wald test and ANOVA test were performed to compare the means of the index according to the socio-economic variables, considering a significance level of 5%. The sample comprised 91.4% of women and 8.6% of men. The average age of the population was 36.4 ± 13.3 years, with 75% having completed elementary school. The mean HEI was 51 points, which features a diet that needs improvement. The population has a monotonous diet with an adequate intake of legumes, but low for fruits, vegetables and dairy products. Comparing the categories of diet quality of individuals, all components, except sodium, showed statistically different median score (p < 0.01). Studies that evaluate the quality of the diet are essential to support the implementation of nutrition education programs targeted to the core of the problem in the populations studied.