A quantum-dot transistor based on silicon self-assembled quantum dots has been fabricated. The device shows staircases and oscillations in the drain current at room temperature. These data are interpreted as due to single electron tunneling through the dots located in the shortest current path between the source and the drain electrodes. The dot size calculated from the data is similar to 7 nm, which is consistent with the size of the self-assembled dots incorporated in the transistor. (C) 1998 American Institute of Physics. [S0003-6951(98)02147-0].