The authors conducted freezing-thawing experiments using a frost susceptible stone to examine the effectiveness of synthetic resins for preservation. A tertiary tuff (Ohya ishi) from Tochigi prefecture, central Japan, was used as stone specimens. In the first experiment three widely used synthetic resins were used: silane (SS-101), epoxy (Araldite CY-230) and acrylic resin (Paraloid B-72). The porosities, residual weights and ultrasonic propagation velocities (Vp) of specimens were measured at every five cycles of freezing-thawing (-10° ~ +10°C; 1 cycle/day). After 10 cycles, no breaking or changes of physical properties were observed on the specimens treated with silane, while the other two resins showed no preservative effects to frost shattering. Various treatments with silane were compared in the second experiment. The specimens were exposed to the same freezing-thawing condition as in the first experiment. Most of the specimens immersed in silane for more than one hour endured 20 cycles of freezing-thawing. The protection effects by the treatment with silane is not due to a hardening effect, because the compressive and tensile strengths of the specimens indicated no significant differences between non-treated and treated ones. But the treatment with silane lowered the hydraulic conductivity of rocks and impeded the water migration which would form ice lenses at frozen parts and would cause breaking. The preservative effectiveness of silane to frost shattering is explained as the impeding effect of water flows through rocks during freezing.