Glass-carbon composite hollow fibers were prepared by extruding a suspension of glass particles in an N-methylpyrrolidone solution of poly(ether sulfone). The fibers were gelled in water and pyrolyzed for 0.5-30 min in a furnace preheated to 1100-1200 degreesC. The resulting composite carbon-glass fibers had about 2.1 min o.d. and 1.3 min i.d. Scanning electron microscopy was used to examine fiber morphology, while the nitrogen permeance was about 7 x 10(-5) Mol/m(2). Pa(.)s, indicating pores of micron size. Compared to pure glass fibers, which are easily deformed at 900 degreesC, the composite fibers could withstand temperatures up to 1200 degreesC without suffering deformation.