The scope of this study was to identify the prevalence and factors associated with food insecurity (INSEC) in families of northern Alagoas. A cross-sectional study was conducted with a random sample of 1444 households classified in accordance with the Brazilian INSEC scale into the following categories: mild, moderate or severe. The prevalence ratio calculated by Poisson regression was used to investigate the association of moderate + severe INSEC with the independent variables in both crude and adjusted analysis. The variables that in the crude analysis reached p < 0.2 were included. INSEC was detected in 919 families, of which, 23.3% and 14.2% were in the moderate or severe form, respectively. There was a higher proportion of food insecurity in the families with subjects < 18 years. The variables that remained independently associated to moderate + severe food insecurity were: rooms in the household ≤ 4, schooling of the household head ≤ 4 years, drinking water other than mineral, beneficiary of the Bolsa Família Program, number of residents in the household > 4, head of household is female and schooling of the housewife ≤ 4 years. The conclusion was that the families studied showed a high prevalence of INSEC, especially those with individuals < 18 years.