We report the electron transport properties of an amorphous organic semiconductor based on silole derivatives. The observed non-dispersive and fast electron transport suggests that electron trapping due to energetic disorder is very small. Based on the mobility measurements in air we conclude that oxygen does not function as a significant electron trap. The observed excellent electron transport properties of this silole derivative are attributed to a large electron affinity originating from its sigma*-pi* conjugation and a high aromaticity of its anionic species.