In a method for detecting a deviation of a compression pressure of one cylinder from that of another cylinder of an internal combustion engine having at least two cylinders, the rotational speed of a crankshaft of the internal combustion engine is reduced from a starting rotational speed to a target rotational speed; the actual rotational speed is detected; a curve of a change of the actual rotational speed per angle unit of the crankshaft is determined as a curve of a rotational speed gradient; the curve of the rotational speed gradient is subjected to order analysis; and a deviation of the compression pressure of one cylinder from that of another cylinder is detected when an amplitude of a selected order lies above a permissible threshold value.