Surrogate decision makers for persons with advanced dementia play a key role in making decisions about medical treatments for their loved ones. We conducted in-depth interviews of 20 surrogates to examine their goals of care preferences and beliefs about personhood. All surrogates believed the goal of comfort was important, and 30.0% believed that curing physical problems was important. Significant proportions of surrogates acknowledged dementia-related changes in patients' ability to reason, communicate, and relate to others. Qualitative findings demonstrated diverse beliefs regarding the impact of dementia on factors related to personhood, for example, dignity, respect from others, and having a life worth living. In conclusion, the surrogates we interviewed expressed diverse preferences regarding goals of care and diverse assessments about the impact of dementia on personhood.