A method for controlling the rotational speed of at least one rotating element in a vehicle's drive line is provided. A first control model and a second control model are defined. The first control model calculates a permitted slippage of at least one of the vehicle's ground-engaging elements at its point of contact with the ground, which ground-engaging element is driven via the rotating element. The second control model calculates a torque delivered to the said ground-engaging element. The result of one of the said control models is utilized for controlling the rotational speed of the rotating element.