A method of operating a clutch serving as a shift element and/or starting clutch of a drive train. During engagement, the clutch will be filled by a fast filling up to a defined minimum pressure. The fast filling is at least subdivided into two phases comprising a basic filling phase and an extension and/or a cutout phase. At the end of the basic filling phase, the actual clutch pressure is measured, and then, when the actual clutch pressure is equal to or larger than the minimum pressure, the extension and/or cutout phase is activated immediately following the basic filling phase. When the actual clutch pressure is lower than the minimum pressure, activation of the extension and/or the cutout phase is at least delayed by a pressure holding phase and, if necessary, by a pressure surplus phase.