Melt spinning process of polymethylsilsesquioxane (PMSQ) at 403-453 K was investigated as a Si-O-C fiber precursor in terms of averages and distributions of spun fiber diameters. Because Of fusible character of PMSQ at low temperature, the spun fibers were exposed to vapors of various metal chlorides (SiCl4, Si(CH3)Cl-3, TiCl4, and BCl3) to promote the fiber curing. Cured fibers were investigated by FTIR and TG analyses. In a case of the fiber synthesized with SiCl4 curing, tensile tests on the pyrolyzed fibers were performed. Exposure of the synthesized fiber at high temperature with a flame of an oxygen-gas burner was examined. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 2600-2607, 2009