ImportanceWhile the health care community advocates broadly for climate change policy, medical professionals can look within care practices to assess their contribution to carbon dioxide (CO2) emissions, and provide solutions wherever possible. Telemedicine can help in mitigating climate change by providing care from a distance.ObjectiveTo assess the carbon savings achieved from telemedicine visits.Design, Setting, and ParticipantsThis cross-sectional study of telemedicine visits was conducted at a single-institution National Cancer Institute (NCI)-designated comprehensive cancer center. Eligible patients were aged 18 years and above, completed telemedicine visits from April 1, 2020, to June 20, 2021, and had a Florida mailing address documented in their electronic medical record. Groups were divided between those within driving time of 60 minutes (1-way) to the cancer center vs those living beyond 60 minutes of drive time. Data were analyzed between April 2020 and June 2021.Main Outcomes and MeasuresCarbon emission savings from telemedicine, measured in total and average per-visit savings.ResultsA total 49 329 telemedicine visits with 23 228 patients were conducted from April 1, 2020, to June 30, 2021. A total 21 489 visits were for patients with driving time of 60 minutes or less (median [IQR] age, 62.0 [52.0-71.0] years; 12 334 [57.4%] female; 1685 [7.8%] Black, 1500 [7.0%] Hispanic, 16 010 [74.5%] non-Hispanic White), while 27 840 visits were for patients with driving time greater than 60 minutes (median [IQR] age, 67.0 [57.0-74.0] years; 14 372 [51.6%] female; 1056 [3.8%] Black, 1364 [5.0%] Hispanic, 22 457 [80.7%] non-Hispanic White). For patients living within a driving time of 60 minutes from the cancer center, 424 471 kg CO2 emissions were saved (mean [SD] emissions savings, 19.8 [9.4] kg CO2 per visit) due to telemedicine—equivalent to 91.5 passenger vehicles driven for 1 year. For patients whose driving distance was greater than 60 minutes, 2 744 248 kg CO2 emissions were saved (mean emissions savings, 98.6 [54.8] kg CO2 per visit)—equivalent to 591 passenger vehicles driven for 1 year.Conclusions and RelevanceUsing a large data set, this cross-sectional analysis highlighted the carbon emissions savings due to telemedicine in oncology. This has important implications in reducing health care–related carbon footprint.