The IR transmittance of silver-halide fibers was measured while they were undergoing various flexing procedures leading to mechanical fatigue. The fatigue experiments consisted of repetitive bending, going from small bending radii (plastic regime) to large bending radii (elastic regime). Various types of fibers have been investigated including unclad fibers, fibers with a core-clad structure, fibers of various AgClxBr1-x compositions and fibers of different diameters. The optical measurements which were done during the flexing experiments involved CO2-laser transmission and spectral (FTIR) transmission. The results for the various conditions are reported and discussed in terms of high-cycle and low- cycle fatigue. Such investigations are of practical importance in characterizing fibers useful for endoscopic surgery and IR detection.