The invention relates to a condition monitoring method and a corresponding system for measuring the stopping accuracy of an elevator car. In the invention, a door zone is defined for each floor, a door zone detector is mounted on the elevator car, the elevator car is moved towards a destination floor, acceleration values of the elevator car are measured during its travel towards the destination floor by means of an acceleration sensor attached to the elevator car and the distance of the stopped elevator from the edge of the door zone is calculated on the basis of the measured acceleration values.