Operation at the ESRF: How we work L. Hardy, JM Filhol, ESRF, BP 220 avenue des Martyrs, 38043 Grenoble Cedex. Abstract The European Synchrotron Radiation Facility (ESRF) is an X- ray source of the third generation. The accelerator complex is composed of a Linear accelerator (e- 200 MeV), a synchrotron (300 metres - 6 GeV) and a Storage Ring (844 metres). One full time operator and one volunteer on shift operate these accelerators from the Control Room (CTRM). We will describe the role of the Operation Group within the Machine Division and its relations with the Experiments Division. We shall explain how the shift rosters are organised, how the information is passed from one crew to another, and we will describe the balance of good sense and procedure required. The safety aspects which come under the responsibility of the operation crew will also be discussed.