A red nanowire LED with an InGaN bulk active region, directly grown on a p-Si (111) substrate, is demonstrated. The LED exhibits relatively good wavelength stability upon increasing injection current and narrowing of the linewidth without quantum confined Stark effect. Efficiency droop sets in at relatively high injection current. The output power and external quantum efficiency are 0.55 mW and 1.4% at 20 mA (20 A/cm2) with peak wavelength of 640 nm, reaching 2.3% at 70 mA with peak wavelength of 625 nm. The operation on the p-Si substrate results in large carrier injection currents due to a naturally formed tunnel junction at the n-GaN/p-Si interface and is ideal for device integration.