Patients who present with medically unexplained illnesses or medically unexplained symptoms (MUI/S) tend to be higher utilizers of health care services and have significantly greater health care costs than other patients, which add stress and strain for both the patient and provider. Although MUI/S are commonly seen in primary care, there is not sufficient information available regarding how providers can increase their level of confidence and decrease their level of frustration when working with patients who present with MUI/S. The goal of this article is to present findings from a qualitative phenomenology study, which highlights medical residents' experiences of caring for patients with MUI/S and the personal and professional factors that contributed to their clinical approaches. Results from these studies indicate that residents often experience a lack of confidence in their ability to effectively treat patients with MUI/S, as well as frustration surrounding their encounters with this group of patients.