Background and Objective: Food insecurity implies lack of access to food necessary for a healthy life, marked by socioeconomic vulnerabilities. We aimed to assess the prevalence and factors associated to food insecurity in Manaus, a city in the Brazilian Amazon. Methods: This was a population-based cross-sectional study conducted in 2019 with adults (≥18 years-old) selected by a probabilistic sampling in three stages. The presence of food insecurity was measured using the Brazilian Household Food Insecurity Measurement Scale adapted and validated in Brazil to measure food insecurity as mild, moderate, or severe. Descriptive statistics was conducted and the prevalence ratios (PR) with 95% confidence interval (CI) were calculated using multinomial logistic regression, adjusted by significant variables at the level of p <0.10. Associations to food insecurity were considered if p<0.05. Stata 14.2 and complex design were used in all analyses. Results: Of the 2,321 participants included in this study, 38.0% (95%CI 36.0-40.1%) had mild; 14.3% (95%CI 12.8-15.8%), moderate; and 15.7% (95%CI 14.1-17.2%), severe food insecurity. Mild, moderate and severe food insecurity was more prevalent in women (mild:PR 1.35, 95%CI 1.08-1.68; moderate:PR 1.61, 95%CI 1.19-2.17; severe:PR 1.48, 95%CI 1.09-2.02), poorest individuals (mild:PR 1.56, 95%CI 1.09-2.23; moderate:PR 6.46, 95%CI 3.38-12.33; severe:PR 6.30, 95%CI 3.27-12.13), people with depressive symptoms (mild:PR 1.41, 95%CI 1.04-1.91; moderate:PR 2.59, 95% CI 1.80-3.72; severe:PR 2.50, 95%CI 1.76-3.54) and that suffered life threatening events in the previous year (mild:PR 1.75, 95%CI 1.39-2.21; moderate:PR 3.94, 95% CI 2.63-5.89; severe:PR 4.46, 95%CI 2.94-6.77). Severe food insecurity was also more frequent in people aged from 45-59 years (PR 2.49, 95%CI 1.50-4.15), and unemployed or housewife (PR 2.91, 95%CI 1.76-4.80). Conclusions: Food insecurity affected more women, the poorest, people with depression, and those who suffered threatening events. Social vulnerabilities and threatening events seem to add up and worsen the right to access to food.