The invention concerns a multi-disk brake (1) in an automatic transmission, with an inner disk carrier (4) and an outer disk carrier (6), with inner disks (3) and outer disks (5) arranged axially in alternation on the disk carriers (4, 6), with friction linings (7) on the inner and/or outer disks (3, 5), with a piston (10) of a pressure-medium-actuated piston-cylinder arrangement such that the inner disks (3) and outer disks (5) can be acted upon by a force to close the multi-disk brake, with an end disk (9) or support disk (11) that forms an axial abutment for the disk set (14) formed by the disks (3, 5, 9, 11), and in which the disk brake (1) and/or the components around it are so configured that the disks (3, 5, 9, 11) can be wetted by a cooling oil. To cool the disk multi-brake (1) even in slip operation phases and in the engaged condition, it is provided that depending on the operating condition of the brake, the cooling oil (13) can be passed over and/or through the disk set (14) in radially different directions. The invention also concerns a method for operating such a disk brake.