A portable lighting fixture for use with a patio umbrella and the like in which the umbrella is supported by a center pole having struts extending outwardly therefrom to the underside of the umbrella when the umbrella is in a raised position. A base has a slot therein extending inwardly from an edge of the base toward the center thereof for receiving the pole to removably install the base below the underside of the umbrella about the pole. The base is supported by the struts when installed. At least one electric light source is mounted on the base. Power is supplied from a source of electrical energy to the light source thereby to illuminate the area beneath the umbrella.