Abstract: The bicycle rear lighting system comprises: a light emitting structure including a first linear array of two or more light emitting diodes which emit light along a first line; first mounting structure for mounting the light emitting structure underneath the rear edge of a bicycle seat; a source of electrical energy coupled to the light emitting structure; second mounting structure for mounting the source of electrical energy to the underside of the bicycle seat; a first switch coupled to the source of electrical energy and to the light emitting structure for connecting and disconnecting the source of electrical energy with the light emitting structure; and the array of two or more light emitting diodes being arranged closely adjacent to each other so that the diverging light beam from each light emitting diode overlaps the light beam from an adjacent light emitting diode thereby to provide a powerful, reinforced light beam along the first line.