Presenteeism refers to attending work while ill. Although it is a subject of intense interest to scholars in occupational medicine, relatively few organizational scholars are familiar with the concept. This article traces the development of interest in presenteeism, considers its various conceptualizations, and explains how presenteeism is typically measured. Organizational and occupational correlates of attending work when ill are reviewed, as are medical correlates of resulting productivity loss. It is argued that presenteeism has important implications for organizational theory and practice, and a research agenda for organizational scholars is presented. Copyright © 2009 John Wiley & Sons, Ltd.