Objective: This study sought to quantify the prevalence of food insecurity among Salvadorian households, to identify the determinants of food insecurity and to explore the impact of the COVID-19 pandemic on food insecurity. Methods: A nationwide, representative random sample of 2358 households was used for this cross-sectional study. The Household Hunger Scale (HHS) was used to assess the prevalence of food insecurity during a 30-day period. For comparison, three items were used from the Household Food Insecurity Experience Scale (HFIES), which measures hunger occurring during a 12-month time frame. For determinant analysis, binary logistic regression was used for the HHS and ordered logistic regression for the HFIES. Results: The prevalence of food insecurity was 6.45% (152/2356) among Salvadorian households when the HHS was used, affecting 5.48% (129/2356) to a moderate degree and 0.98% (23/2356) to a severe degree. The prevalence significantly increased when the HFIES scale items were used, with 35.41% (835/2358) of households being affected, a figure closer to the national poverty level. Determinants of food insecurity according to the HHS included agricultural problems (P = 0.00, odds ratio [OR] =1.69), the household's prepandemic income (P = 0.00, OR = 0.48) and higher educational levels (i.e. having a secondary education [P = 0.00, OR = 0.31], technical [P = 0.03, OR = 0.24] or university education [P = 0.00, OR = 0.05]). When using the HFIES, the determinants were similar (i.e. income, agricultural problems, educational level). In more than 94% (744/785) of households, participants reported that food insecurity was exacerbated by the COVID-19 pandemic. Conclusions: When compared with other relevant international studies, the prevalence of food insecurity identified using the HHS - only 6.45% - was low for El Salvador. However, when using the HFIES scale, the prevalence rose to 35.41% of households. Some determinants align with previous studies, namely income, educational level and agricultural problems. The COVID-19 pandemic appeared to have direct effects on food insecurity.