The effect of polymeric coatings on the static fatigue of tightly jacketed double-coated optical fibers is theoretically analyzed. A closed form solution of the tensile stress in the glass fiber is obtained from viscoelastic theory. The tensile stress in the glass fiber in the static fatigue test increases with time due to the viscoelastic behavior of the polymeric coatings, and this increase will accelerate the failure of the optical fiber. The long-term strength of optical fibers can be improved by increasing the axial rigidities and the relaxation times of the secondary coating and the tight jacket. Finally, a rule to prevent the overestimation of fiber's lifetimes in the static fatigue test is proposed. (C) 2003 Published by Elsevier B.V.