Several laboratories have reported digital data acquisition and control systems for electron microscopes. The considerations involved in implementation of such a system have been reviewed. All of these systems have used a relatively small minicomputer, either as a stand-alone, or as a satellite processor linked to a larger computer, so as not to burden the large host with the mundane task of operating a microscope. In recent years however, hardware costs have decreased sufficiently that many laboratories have their own superminicomputer (e.g., one of the Digital VAX series), or share one within a small group of users.