Telemedicine is being used across OECD countries to deliver health care in a wide range of specialties, for numerous conditions and through varied means. A growing body of evidence suggests that care delivered via telemedicine can be both safe and effective, in some cases with better outcomes than conventional face-to-face care. Telemedicine services can also be cost-effective in different settings and contexts. However, despite these benefits, these services still represent a small fraction of all health care activity and spending. Important barriers to wider use remain, with providers and patients facing regulatory uncertainty, patchy financing and reimbursement, and vague governance. Due to inequalities in health and digital literacy, patients that most stand to benefit are also often those that are least able to access and make use of telemedicine. Telemedicine has the potential to improve effectiveness, efficiency and equity in health care, but can also introduce new risks and amplify existing inequalities.