A method for damping a power train oscillation in a vehicle provided with a prime mover which rotates at a speed ω. A vibration change S in the rotation speed ω of the prime mover is determined. There is deemed to be a power train oscillation if for a predetermined number of times the amplitude of the vibration change S is alternately above a positive threshold value Th1 and below a negative threshold value Th2 and if all of the consecutive upward crossings of the positive threshold value Th1 and downward crossings of the negative threshold value Th2 are separated by a time shorter than a predetermined period T.