SiC-based fibers and powders with ∼20 nm crystallite size were prepared by carbothermal reduction of silica/carbon mixtures. The reactant mixtures were prepared by solution-based processing in which tetraethoxysilane (TEOS) was the silica-bearing precursor and phenol-formaldehyde resin was the carbon-bearing precursor. Fine-diameter fibers were prepared by dry spinning mixed sols that had been concentrated to high viscosity.