High-quality, hexagonal phase, mesoporous silica fibers (see Figure) can be grown by the general procedure for one-step, two-phase, room temperature synthesis reported here. The silica fibers, which are 1-5 mu m in diameter and up to 5 cm long, have excellent long-range order, a narrow pore size distribution, and a pore volume of up to 0.78 cm(3)/g. The birefringent fibers can be used as high-surface-area optical fibers.