Informal caregivers are increasingly performing medical/nursing tasks in the home for adult care recipients, often without adequate support. In the current study, using data from the Caregiving in the U.S. 2015 survey (N = 1,248), we examined associations between performing medical/nursing tasks and caregiver well-being (e.g., physical strain, emotional stress, burden of care). Overall, 58% of caregivers performed medical/nursing tasks. Compared to those who did not, those performing tasks had higher risk of emotional stress, physical strain, and high burden of care. Among task performers, difficulty performing tasks was associated with higher risk of all outcomes; having no choice in caregiving was independently associated with higher risk of emotional stress and physical strain. Caregivers performing medical/nursing tasks, particularly those who find tasks difficult, are at risk for adverse outcomes. New clinical approaches are needed to ensure meaningful conversations about caregivers' willingness, availability, and ability to perform medical/nursing tasks and to provide support for this part of the caregiving role.