Objective: This study was designed to understand the level of familiarity of US rheumatologists, gastroenterologists and dermatologists with biosimilar therapies, their experience with non-medical switching (switching medications for reasons unrelated to patient health) of patients between biologics and their attitudes towards switching from a biologic to a biosimilar.Methods: A total of 297 US physicians who currently prescribe biologics for their patients completed a 15-minute online survey. Rheumatologists, dermatologists and gastroenterologists were included.Results: The majority of physicians (84%) did not want stable patients undergoing a non-medical switch to a biosimilar. While 60% of physicians believed non-medical switching to biosimilars may have a positive impact on healthcare system costs, multiple negative impacts were also expected. A majority of physicians anticipated a negative impact on patient mental health (59%), treatment efficacy (57%), patient safety (53%) and physician office management (60%).Conclusions: The majority of physicians had concerns regarding non-medical switching to biosimilars and the impact such switching would have on patient care and physician practice.