We have measured the density of amorphous carbon (a-C) prepared using electron-beam-induced deposition with a nanotube cantilever. The a-C mass was proportional to the deposition time for all experimental conditions. The measured density ranged from 0.29 to 0.88 g/cm(3) depending on the electron-beam conditions. Density increased with increasing acceleration voltage and beam current. This phenomenon is discussed in terms of the effects of acceleration voltage and beam current on the temperature of the growing surface and the lifetime of the precursor. (c) 2005 American Vacuum Society.