Parylene-C is a vapor-deposited, colorless, transparent polymer that may have applications in the consolidation of fragile, porous, or fibrous art objects. Tests were conducted to determine the effects of a 0.75 mum Parylene-C coating on the tensile and appearance properties of modern and historic silk fabrics. Accelerated thermal and light aging of coated and uncoated silk were conducted and degradation rates were determined for modern silk fabric. Thermal degradation rates of the tensile properties (breaking-load, strain-to-break, and energy-to-break) and the rate of yellowing of a modern silk fabric were unaffected by the presence of the coating. Photodegradation of coated silk fabric resulted in a reduction of tensile properties and yellowing of the coating that was exposed to xenon-arc radiation filtered to simulate outdoor exposure to sunlight. No color developed in free films of Parylene-C after exposure to the source that was filtered through a 400 nm cut-off filter. The effect of coating structurally strong, modern silk was an increase in all tensile properties with the exception of the initial modulus. Coating comparatively weak, historic silk increased the breaking-load, energy-to-break, and the initial modulus but did not result in an increased strain-to-break. This method of consolidation could be considered for the conservation of very fragile silk where added strength is the primary consideration and exposure to ultraviolet light is minimized.