A thermal jacket shield for a drilling motor which permits drilling operations in high temperature wells without failure of the motor. The thermal shield includes a multiple passageway casing to shroud the motor and through which is circulated drilling fluid used to operate the drilling motor. The motor is positioned within concentric inner and outer shells which form a fluid annulus through which the fluid is circulated. An intermediate housing sub connected to the lower end of the drilling motor includes a nozzle through which a controlled quantity of drilling fluid is passed into the annulus formed by the inner and outer annular shells. Outlet ports in the outer shell allow the drilling fluid to flow to the exterior of the tool. As a result, cooling fluid is continuously passed through the jacket shield to maintain the operating temperature of the motor at an acceptable temperature.