Separate cross-sectional surveys were administered to patients and physicians to ascertain current practices and preferences for e-mail communication by each group. A chart review was conducted to assess the impact of e-mail communication on care. WHAT WE FOUND: Approximately 41% of patients reported previous contact with a member of their health care team. Eighty percent of physicians reported previous contact with a patient via e-mail. All physicians reported using e-mail regularly with other health care providers to manage care. Patient factors associated with higher likelihood of e-mail contact with the health care team included younger age, higher education, higher income, enrollment in a clinical trial, and receipt of multiple treatments. Physician factors associated with higher likelihood of e-mail contact with patients included older age, more senior clinical position, and higher patient volume. Both patients and physicians saw value in e-mail communication for certain clinical scenarios. In terms of concerns with using e-mail to communicate, patients' main concerns related to confidentiality and e-mail not being received whereas physicians were concerned about miscommunication and workload. E-mail correspondence was documented in only 9% of 962 charts reviewed. BIAS, CONFOUNDING FACTOR(S), DRAWBACKS: This is a single-center study in a large comprehensive cancer center so it is unknown whether these results would be applicable to smaller centers. The response rate to the physicians survey was low. Finally, due to the low frequency of documented e-mail communications, we were unable to evaluate the impact on patient care. REAL-LIFE IMPLICATIONS: Patients and physicians are commonly using e-mail to communicate about health care matters and this use can be further developed with appropriate guidance. The use of patient portals with direct links to e-mail communication are likely to change this field significantly. There may also be concerns about widening the health care gap for certain groups of patients, so care must be taken to avoid this.