OBJECTIVES: To quantify the magnitude of altruism value as applied to a hypothetical new treatment for a rare, severe pediatric disease: Duchenne muscular dystrophy (DMD). STUDY DESIGN: Prospective survey of individuals not planning to have children in the future. METHODS: A survey was administered to US adults (aged ≥ 21 years) not intending to have a child in the future to elicit willingness to pay (WTP) for government insurance coverage for a new hypothetical DMD treatment that improves mortality and morbidity relative to the current standard of care. A multiple random staircase design was used to identify an indifference point between status quo government insurance coverage and coverage with additional cost in taxes that would cover the treatment if unrelated individuals had a child with DMD. Altruism value was calculated as respondents' mean WTP. RESULTS: Among 215 respondents, 54.9% (n = 118) were aged 25 to 44 years and 80.0% (n = 172) were women. Mean WTP for insurance coverage of the hypothetical DMD treatment for others was 0.01 (95% CI, 1.64- 18.37) annually, or .67 monthly, after adjustment to account for disease probability overestimation. The adjusted altruism value was higher than the ex ante per-person value using traditional cost-effectiveness approaches ( 5.30/year). Without adjusting, individuals were willing to pay 99.11 annually ( 6.59 monthly). CONCLUSIONS: Despite no possibility of accruing health benefits directly for themselves or their children, individuals had a high WTP for government insurance coverage of a novel treatment for this rare, severe pediatric disease.