BACKGROUNDThere is limited evidence from nationally representative samples about changes in prescription drug use for financial reasons among cancer survivors in the United States. METHODSThe 2011 to 2014 National Health Interview Survey was used to identify adults who reported ever having been told they had cancer (cancer survivors; n = 8931) and individuals without a cancer history (n = 126,287). Measures of changes in prescription drug use for financial reasons included: 1) skipping medication doses, 2) taking less medicine, 3) delaying filling a prescription, 4) asking a doctor for lower cost medication, 5) buying prescription drugs from another country, and 6) using alternative therapies. Multivariable logistic regression analyses were controlled for demographic characteristics, number of comorbid conditions, interactions between cancer history and number of comorbid conditions, and health insurance coverage. Main analyses were stratified by age (nonelderly, ages 18-64 years; elderly, ages 65 years) and time since diagnosis (recently diagnosed, <2 years; previously diagnosed, 2 years). RESULTSAmong nonelderly individuals, both recently diagnosed (31.6%) and previously diagnosed (27.9%) cancer survivors were more likely to report any change in prescription drug use for financial reasons than those without a cancer history (21.4%), with the excess percentage changes for individual measures ranging from 3.5% to 9.9% among previously diagnosed survivors and from 2.6% to 2.7% among recently diagnosed survivors (P < .01). Elderly cancer survivors and those without a cancer history had comparable rates of changes in prescription drug use for financial reasons. CONCLUSIONSNonelderly cancer survivors are particularly vulnerable to changes in prescription drug use for financial reasons, suggesting that targeted efforts are needed. Cancer 2017;123:1453-1463. (c) 2016 American Cancer Society. Cancer survivors in the United States are more likely to change their prescription drug use for financial reasons than individuals without a cancer history. Survivors younger than 65 years and those who have multiple comorbid conditions are especially vulnerable to the financial burden associated with prescription drugs. See also pages 1301-2.