The durability of two extruded thin sheet PVA fiber-reinforced cement composites were investigated. The baseline composition contained silica fume and other replaced the silica fume in the baseline composition with OPC. Compositions were subjected to aging in a 50% relative humidity room, immersion in a 50 ? waterbath. and exposure to freeze-thaw cycling. Samples were tested primarily in the saturated condition and less frequently in the dry condition. Strength and toughness values were obtained from 3-point fiexural and notched tensile tests. The effects of aging, silica fume content, and testing condition were considered. Each composition, tested in both the saturated and diy conditions and tested for all types of aging, experienced si miliar trends: a decrease in fluxural strength and flexural first crack stress, an increase in tensile strength and tensile first crack stress, and a decrease in toughness values. Although both the non-aged and aged specimens experienced fiber pullout, the mechanism of bond failure appears to be different. The contribution of silica fume was not significant as far as duribility is concerned. Strength increased with drying, and toughness generally decreased.