Asthma is one of the most common chronic diseases in the U.S. Despite guidelines, adherence to recommended controller medications is low. Cost is an important barrier to adherence. Employers are increasingly adopting high-deductible health plans (HDHPs) which require deductibles of > $1,000 per individual/$2,000 per family each year. In HDHPs with Health Savings Accounts (HSAs), most medications and non-preventive care must be paid out-of-pocket (OOP) until the deductible is reached. The lower premiums of HSA-HDHPs are appealing, but the high level of OOP costs can lead patients to forgo needed care. HSA-HDHPs can exempt preventive care from the deductible, and employers can add Preventive Drug Lists (PDLs) which exempt certain chronic medications from the deductible (including asthma medications), making them free. PDLs have the potential to improve controller medication use, which could prevent negative health outcomes and reduce cost-related trade-offs for families.