PURPOSE: To quantify the association between food insecurity and smoking among low-income families. DESIGN AND SETTING: A retrospective study using data from the 2001 Panel Study of Income Dynamics (PSID), a longitudinal study of a representative sample of U.S. men, women, and children and the family units in which they reside. SUBJECTS: Low-income families. MEASURES: Family income was linked with U.S. poverty thresholds to identify 2099 families living near or below 200% of the federal poverty level. Food insecurity (i.e., having insufficient funds to purchase enough food to maintain an active and healthy lifestyle) was calculated from the 18-core-item food security module of the U.S. Department of Agriculture. Current smoking status was determined. RESULTS: Smoking prevalence was higher among low-income families who were food insecure compared with low-income families who were food secure (43.6% vs. 31.9%; p < .01). Multivariate analysis revealed that smoking was associated with an increase in food insecurity of approximately six percentage points (p < .01). CONCLUSIONS: Given our finding that families near the federal poverty level spend a large share of their income on cigarettes, perhaps it would be prudent for food-assistance and tobacco-control programs to work together to help low-income people quit smoking.