In 2016 fee-for-service Medicare began reimbursing physicians for advance care planning conversations with enrollees during outpatient visits and waived the copayment for advance care planning when it was part of the Medicare annual wellness visit. Advance care planning is intended to help providers treat patients in ways consistent with their wishes and may also reduce unnecessary health care use and spending. Examining fee-for-service Medicare claims, we found a substantial increase in outpatient advance care planning claims between 2016 and 2019, although prevalence remained below 7.5 percent for all patient subgroups analyzed.