Our study objectives were to (1) identify the national prevalence and patterns of food insecurity among adults with and without a history of CMCs and (2) determine associations between food insecurity and mental health outcomes among adults with CMCs during the early COVID-19 pandemic period (April–June 2020). We computed prevalence ratios with Poisson regression using the robust estimation of standard errors to identify disparities in the report of food insecurity across demographic groups and by CMC history. Among adults with CMCs, we estimated associations between food insecurity and self-reported mental health symptoms using multinomial logistic regression. Overall, people with CMCs were more likely to be older, White, without employment in the past 7 days, and from the South or an urban environment. We found that the determinants of food insecurity among individuals with cardiometabolic conditions include having: <60 years of age, female sex, Black or Hispanic race/ethnicity, an educational degree lower than a baccalaureate, a household income of <$100,000, and either Medicaid, Indian Health Insurance, or no insurance. Individuals with CMCs and food insecurity also had significantly higher odds of adverse mental health symptoms. The continued clinical screening of food insecurity and mental health, as well as public health interventions, targeted toward individuals with CMCs, should be prioritized as we move through the COVID-19 pandemic.