Objective: To evaluate the New York State Expanded Food and Nutrition Education Program using economic methodology. Design: Data were collected by nutrition educators in a pretest, posttest design with an epidemiological modeling approach to assess costs and estimate potential health benefits of the state program. Setting: Cooperative Extension, 35 counties. Participants: 5730 low-income participants. Intervention: Series of 6 or more food and nutrition lessons. Main outcome measures: Cost (program and participant); health benefits in quality adjusted life years (QALYs); and monetized benefits: society's willingness to pay for QALYs, and benefits of avoiding or delaying health care costs and loss of productivity. Analysis: Cost-effectiveness estimated from behavior change and QALY weights. Cost-benefit ratios estimated from costs and monetized benefits. Sensitivity analyses provided ranges where lack of agreement exists around parameters' values. Results: Cost was $892/graduate. Cost-effectiveness was 245 QALYs saved, at $20 863/QALY (sensitivity 42-935 QALYs, $5467-$130 311 per QALY). Societal willingness to pay benefit-to-cost ratio was $9.58:$1.00 (sensitivity $1.44-$41.92:$1:00); narrow governmental benefit-to-cost ratio was $0.82:$1.00 (sensitivity $0.08-$4.33:$1:00). Conclusions and implications: Outcome data indicate that food and nutrition behavior changes resulting from the Program are likely to improve future health and reduce health care costs. Cost-effectiveness is estimated to be as great as for many current health interventions.