As the prevalence of Alzheimer's disease (AD) increases, the need to develop effective and well-tolerated pharmacotherapies for the prevention of AD is becoming increasingly important. Understanding determinants and magnitudes of individuals' preferences for AD prevention programs is important while estimating the benefits of any new pharmacological intervention that targets the prevention of the disease. This paper applied contingent valuation, a method frequently used for economic valuation of goods or services not transacted in the markets, to estimate the willingness-to-pay (WTP) to prevent AD based on the nationally representative Health and Retirement Survey data. The WTP was associated in predictable ways with respondent characteristics. The mean estimated WTP for preventing AD is $155 per month (95 % CI $153-$157) based on interval regression. On average, a higher WTP for the prescription drug for AD prevention was reported by respondents with higher perceived risks, and greater household wealth. The findings provide useful information about determinants and the magnitude of individuals' preferences for AD prevention drugs for healthcare payers and individual families while making decisions to prevent AD.