We report on measurements of room-temperature electroluminescence from single silicon nanocrystals. The electrically driven emission reveals typical characteristics of single-nanocrystal luminescence: the peak wavelength variations, narrowing of spectral bands, a high degree of linear polarization, and intensity fluctuations (blinking) observed on a scale of minutes. From the count rate statistics of individual nanocrystals, we conclude that the yield of radiative emission is as high as 19%. These findings may open a route to highly efficient all-silicon light emitters. © 2004 American Institute of Physics.