The invention relates to a fall detection system, for detecting human fall incidents. The detection system comprises a sensor module to be worn by a user, for collecting motion data of his body, for instance acceleration data; first evaluation logic for identifying a potential fall incident on the basis of an impact observed in the acceleration data; and second evaluation logic for verifying that the sensor module is actually worn by the user, at least around the time of said impact, to prevent the system from raising an alarm if only the sensor module has fallen. The second evaluation logic may comprise free fall detection means for evaluating the acceleration data on characteristics which are typical for a free falling object, such as one or more full rotation and/or a free falling phase, during which the magnitude of the acceleration data is relatively stable and small. Additionally or alternatively the second evaluation logic may comprise body proximity detection means for detecting whether the sensor module is in close proximity to the human body.