Nylon yarns conditioned in different relative humidities were textured in both dry and wet modes, and the effect of these factors on the structure and properties of air textured yarns was investigated. Results suggest that friction plays a more important role than modulus, and the marked improvement in structure and properties of textured yarns brought about by wet texturing despite increased friction due to wetting cannot be ascribed to a reduction in the modulus of filaments. The changes in the fluid behavior inside the jet may be playing a vital role in influencing the texturing behavior of filaments in the presence of water.