An optoelectronic sensor (10), in particular a light barrier having a light transmitter (14) for the transmission of a light beam (18) and a light receiver (26) arranged facing the light transmitter (14) at an alignment angle to transform the received light beam (18) into an electrical received signal is provided, wherein the transmission power of the light transmitter (14) and/or the reception sensitivity of the light receiver (26) is/are set, such that the received signal has an intensity distribution varying in accordance with the alignment angle and wherein an evaluation unit (28) of the sensor (10) is configured to determine by means of the received signal whether the light beam (18) is interrupted or not. In this respect the intensity distribution is stored in a memory (28a) of the sensor (10) and in that the evaluation unit (28) is configured to determine, with reference to the measured intensity of the received signal from a measured intensity distribution, a lower threshold (38) and an upper threshold (40) whose separation corresponds to an accepted angular range.