Abstract: A rotor for an internal gear pump adapted to improve the lubrication of the internal gear parts. A radial groove is added to the inner face of an internal rotor. The groove extends radially between the center of the rotor and an outer diameter of the rotor. The groove provides a communication channel between the outer circumference of the rotor and the parts located within the rotor's inner diameter, namely the idler gear and idler pin. The disclosed grooved rotor improves the flow of fluid to the interface between the idler gear and the idler pin of a typical internal gear pump. Should the lubricating properties of the fluid be reduced and/or the operating pressures of the pump increased, the improved rotor design will provide lubrication of the internal rotary parts, thereby decreasing the friction among the parts and extending the overall productive life of the pump.