An optoelectronic sensor and a method for producing a positive or a negative object detection signal in dependence on the presence or non-presence of an object in a foreground region or in a background region of a region monitored by the sensor. Transmitted light is transmitted in the direction of the monitored region during an operating phase. A plurality of received signals are produced in dependence on the reflected and the received transmitted light which are associated with the foreground region or with the background region. A difference of the received signals is compared with a differential threshold to produce the positive or the negative object detection signal, wherein a switching hysteresis is formed for a change between the positive and the negative object detection signal. The association of the received signals with the foreground region and the background region is changed in dependence on a change in the object detection signal to form the switching hysteresis.