© 2015 American Chemical Society. An objective of the present paper is to study the surface crystallization of optical fibers made of quartz glass during the drawing process. Calculations based on the rates of fiber cooling and the crystallization process reveal formation of a cristobalite layer on the surface about 6 nm thick. The infrared reflection spectra of the quartz fibers, their pictures obtained with an electron microscope, and the thermal treatment results confirm the occurrence of a cristobalite layer on the fiber surface.