Aramid fibers are high-performance materials which have been used in ropes and protective clothing for many years. They are also now being proposed in geo-textiles for ground reinforcement. The influence of the surface finish composition and content has been studied in the field of cables and textiles, but there is no published data concerning the effect of a finish treatment on the hydrolytic degradation. Aramid fibers with different finish contents have been aged in an alkaline environment. The degradation has been identified by FTIR, viscosimetry, TGA, SEM, and tensile tests. For Technora fibers, the presence of finish appears to limit the tensile strength loss of aramid fibers at pH 11 by limiting abrasion, as well as bulk and surface degradation. For Twaron fibers, higher finish content only has a slight influence on the fibers durability at pH 11 and pH 9, by limiting abrasion and bulk degradation. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 888-898, 2010