OBJECTIVES: Spinal muscular atrophy (SMA), the most common fatal genetic disease among children, is not included in current U.S. mandatory newborn screening panel.  We assessed how much, if anything, people would pay for testing their newborns for SMA, and how test preferences varied depending on immediate treatment implications. METHODS: We conducted a population-based willingness-to-pay (WTP) online survey.  Respondents were asked to imagine being parents of a newborn.  Each respondent was presented with two sets of hypothetical scenarios following the SMA screening test: current standard of care (SOC, no treatment available) and one of three randomly-assigned treatment scenarios (new treatment available to improve functioning, survival, or both).  We used a double-bounded, dichotomous-choice bidding game to elicit WTP for the SMA test, and performed a two-part model to estimate median and mean WTP values. RESULTS: