A cancer diagnosis is associated with substantial economic burden for patients and their families. Young adult cancer survivors with dependent children may be particularly vulnerable to financial hardship. To examine associations of parental cancer with their children's unmet economic needs. This cross-sectional study used data from the nationally representative 2013 to 2018 US National Health Interview Survey. Children aged 5 to 17 years living in families with and without parental cancer history were queried about recent 1-year experiences. Statistical analyses were conducted from January 2022 to April 2023. Parental cancer history. The main outcomes were children's unmet economic needs, including family-level food insecurity, parent's financial worry about paying for monthly bills and housing costs, and delayed child medical care owing to lack of transportation. Multivariable logistic regressions adjusted for (1) child's characteristics (ie, age group, sex, and race and ethnicity), (2) parent's characteristics (ie, age group, sex, health insurance coverage, comorbid conditions, and obesity status), and (3) family's characteristics (ie, family structure [married or cohabiting parents vs single parent families], highest educational attainment in the family, and family income). Additional analyses focused on children with a parental cancer history to identify potentially modifiable characteristics associated with unmet economic needs. In this cross-sectional study of 22 941 children with (812 children; weighted number, 860 488 children) and without (22 129 children; weighted number, 24 545 463 children) a parental cancer history, the majority of children were aged 5 to 11 years (12 022 children [52.4%]), male (11 920 children [52.0%]), and non-Hispanic White (11 863 children [51.7%]). In adjusted analyses, parental cancer history was associated with more severe family-level food insecurity, including worrying about food running out (odds ratio [OR], 1.97; 95% CI, 1.56-2.49; P < .001), food not lasting (OR, 2.01; 95% CI, 1.56-2.58; P < .001), and inability to afford balanced meals (OR, 1.38; 95% CI, 1.06-1.79; P = .02). Moreover, parental cancer history was associated with parent's worry about paying monthly bills (OR, 1.41; 95% CI, 1.15-1.74; P = .001) and housing-related costs (OR, 1.31; 95% CI, 1.07-1.60; P = .009) and delays in child medical care because of lack of transportation (OR, 2.31; 95% CI, 1.49-3.59; P < .001). Among children with parental cancer history, female children, non-Hispanic Black children, children whose parents had multiple comorbidities, and children living in low-income families were especially vulnerable to unmet economic needs. Parental cancer is associated with greater likelihood of food insecurity, unaffordability of housing and other necessities, and transportation barriers to medical care for minor children. Strategies to identify such children and address their needs are warranted.