Food insecurity is a source of daily stress, especially in women. The aim was to investigate the association between mental distress and food insecurity in pregnant women. Cross-sectional study with pregnant women from the public health service, regardless risk stratification, or gestational trimester in Colombo-PR, Brazil. Poisson regression models were progressively adjusted for exposure variables. Results: Among the participating pregnant women (N=513) the prevalence of mental distress was 50.1%; associated with mild food insecurity (PR 1.34, 95%CI 1.12; 1.61) and moderate/severe food insecurity (PR 1.70, 95%CI 1.33; 2.19). The variable that most changed the association between the outcome and mild food insecurity was income (-4.48%) and, for moderate/severe food insecurity, education (-7.60%). For mild and moderate/severe food insecurity, the greatest reduction occurred with socioeconomic variables 4.5% (PR 1.27, 95%CI 1.05; 1.53) and 8.0% (PR 1.50, 95% CI 1.17; 1.93), respectively. The association between food insecurity and mental distress was consistent, and increased with the degree of food insecurity, with a greater reduction for socioeconomic variables.