Potentially inappropriate prescribing in older adults can increase the risk of adverse drug events (ADEs). This systematic review assessed increased healthcare costs associated with ADEs related to potentially inappropriate medications (PIMs) among older adults. Higher costs were due to increases in hospitalizations, health care expenses, and emergency department visits. Costs were higher among patients with more than one PIM, patients older than 75 years of age, patients with dementia, and patients with other drug interactions.