We present current density-voltage characteristics of Ge quantum dot p+-i-n+ tunneling diodes. The diode structure with Ge quantum dots embedded in the intrinsic region was grown by low temperature molecular beam epitaxy without any postgrowth annealing steps. The quantum dot diodes were fabricated using a low thermal budget fabrication process which preserves the Ge quantum structure. A negative differential resistance at room temperature of a Ge quantum dot tunneling diode was observed. A maximum peak to valley ratio of 1.6 at room temperature was achieved.