A method of operating a vehicle drive train with a drive machine and a transmission device during a coasting upshift, during which at least one interlocking shift element that is engaged in the force flow of the transmission device, to produce the gear ratio to be disengaged, is disengaged from the force flow, and a frictional shift element that has to be engaged, in the force flow of the transmission device to obtain the gear ratio to be engaged, is engaged in the force flow. When a shift command is given for a gear ratio change, torque applied at the interlocking shift element to be disengaged is reduced to at least approximately zero, by a defined engine intervention, and the interlocking shift element is then disengaged from the force flow of the transmission device.