The considerations that influence the selection of polymers and spmning conditions for the purpose of preparing a high-strength, low-elongation type of polyvinyl alcohol fiber for use as a reinforcing component in rigid, cold-hardening resins are discussed. A number of polyvinyl alcohol products from commercial sources were spun, and their fibers evaluated. The two products that gave the best over-all results yielded fibers with a tensde strength of 9-10 g/den and a breaking elongation of 4.5-5%. Elongations at break as small as 3.5% were obtamed with two low-molecular-weight samples. ' To attain optimum values of strength and stiffness with any polyvinyl alcohol, a careful build-up of the fiber fine structure is necessary. This was brought about in wet spinning by slowing down fiber coagulation, as well as other processing steps.