Despite decades of low utilization, telemedicine adoption expanded at an unprecedented rate during the COVID-19 pandemic. This study examined quantitative and qualitative data provided by a national online sample of 228 practicing physicians (64% were women, and 75% were White) to identify facilitators and barriers to the adoption of telemedicine in the United States (U.S.) at the beginning of the COVID-19 pandemic. Logistic regressions were used to predict the most frequently endorsed (20% or more) barriers and facilitators based on participant demographics and practice characteristics. The top five reported barriers were: lack of patient access to technology (77.6%), insufficient insurance reimbursement (53.5%), diminished doctor-patient relationship (46.9%), inadequate video/audio technology (46.1%), and diminished quality of delivered care (42.1%). The top five reported facilitators were: better access to care (75.4%), increased safety (70.6%), efficient use of time (60.5%), lower cost for patients (43%), and effectiveness (28.9%). Physicians' demographic and practice setting characteristics significantly predicted their endorsement of telemedicine barriers and facilitators. Older physicians were less likely to endorse inefficient use of time (p < 0.001) and potential for medical errors (p = 0.034) as barriers to telemedicine use compared to younger physicians. Physicians working in a medical center were more likely to endorse inadequate video/audio technology (p = 0.037) and lack of patient access to technology (p = 0.035) as a barrier and more likely to endorse lower cost for patients as a facilitator (p = 0.041) than providers working in other settings. Male physicians were more likely to endorse inefficient use of time as a barrier (p = 0.007) than female physicians, and White physicians were less likely to endorse lower costs for patients as a facilitator (p = 0.012) than physicians of color. These findings provide important context for future implementation strategies for healthcare systems attempting to increase telemedicine utilization. Author summary: Many physicians treated patients via telemedicine to maintain social distancing during the COVID-19 pandemic. We surveyed a group of U.S. physicians to identify barriers and facilitators of using telemedicine at the beginning of the pandemic. Lack of patient access to technology necessary for telemedicine was the top barrier reported by the physicians. Improving patient access to care was the top facilitator. We also found that the physicians' age, gender, race, and practice setting influenced their opinions. Older physicians were less likely to report wasting time (such as troubleshooting technological issues) and increased possibility of making medical errors as barriers than younger physicians. Male physicians were more likely to report wasting time (such as troubleshooting technological issues) as a barrier than female physicians. White physicians were less likely to report cheaper cost as a facilitator than minority physicians. Physicians working in a medical center were more likely to report poor quality of telemedicine technology and lack of patient access to technology necessary for telemedicine as barriers and cheaper cost for patients as a facilitator. These findings may be helpful for healthcare systems to consider when implementing telemedicine practice in the future.