Method for reading a barcode by means of an optical reader arranged to capture at a determined sampling frequency a series of partial images of the barcode by a sensor having at least one line of pixels. According to the invention it is provided to determine in each partial image a logical value as a function of the light intensity received by a central pixel of the line of pixels and a corresponding bar width when this bar is completely incorporated into the partial image in question. By only setting a maximum speed for the speed of movement of the barcode and dimensioning the line of pixels to ensure that each bar of this barcode is completely incorporated into a partial image at least once, the sequence of bits defined by the barcode is determined by means of an algorithm ignoring the duplications detected in consecutive partial images.