A user-based study of electronic mail was conducted at the World Bank headquarters in Washington, DC. Quantitative and qualitative data were collected from members of 4 large-scale units to generate an accurate and robust picture of the use and impact of e-mail. Each unit contained a representative proportion of support- and professional-level staff. Organizational mission and job role were expected to influence the needs and usage styles of employees with respect to information technology. A highly structured standardized survey gathered information about the nature and volume of electronic communication. In-depth qualitative data were collected from focus groups of participants. Analyses showed that e-mail has become a widely used and popular communication medium at the World Bank. However, a number of technical and organizational constraints currently inhibit the potential of e-mail to serve as a generic infrastructure to support the diverse needs of knowledge workers.