The authors describe the process of initiating an e-mail reference service in June 1995 at the Ohio State University Health Sciences Library and the growth of the set-vice through December 2000. Data on increases in the number of questions over five and a half years, types of patrons who use the service, and types of questions and answers are presented. Issues that arose while providing e-mail reference services have caused the librarians at this library to rethink the services they provide to all patrons, regardless of the means of contact, and to integrate e-mail reference more effectively into the library's overall reference services.