OBJECTIVE To review systematically the role of e-mails in patient-provider communication in terms of e-mail content, and perspectives of providers and patients on e-mail communication in health care. METHODS A systematic review of studies on e-mail communication between patients and health providers in regular health care published from 2000 to 2008. RESULTS A total of 24 studies were included in the review. Among these studies, 21 studies examined e-mail communication between patients and providers, and three studies examined the e-mail communication between parents of patients in pediatric primary care and pediatricians. In the content analyses of e-mail messages, topics well represented were medical information exchange, medical condition or update, medication information, and subspecialty evaluation. A number of personal and institutional features were associated with the likelihood of e-mail use between patients and providers. While benefits of e-mails in enhancing communication were recognized by both patients and providers, concerns about confidentiality and security were also expressed. CONCLUSIONS The e-mail is transforming the relationship between patients and providers. The rigorous exploration of pros and cons of electronic interaction in health care settings will help make e-mail communication a more powerful, mutually beneficial health care provision tool. CONCLUSIONS It is important to develop an electronic communication system for the clinical practice that can address a range of concerns. More efforts need to be made to educate patients and providers to appropriately and effectively use e-mail for communication.