Abstract: A process for determining the lubricant power of lubricant oils for slip-controlled clutches. In a test container (14) consisting of a double-walled, temperable vessel and filled with test lubricant oil, two friction partners (6, 8) are rotated against each other under a test load with practical conditions. A coefficient of friction characteristic curve (27, 28) is determined depending on the sliding speed. If in a working range (26) a progressive characteristic curve is obtained, the lubricant oil is suitable for use in slip-controlled clutches. Since the device required to carry out the process has a relatively simple structure and requires only a small amount of test lubricant oil, the process and device can be used to test production charges in lubricant oil development, during test bench or field tests and to test aging processes in a laboratory.