Moisture content is the environmental factor that has the greatest influence on the physical and mechanical properties of wood materials. This research aimed to quantify the effect of moisture content on the elastic constants of Scots pine wood grown in Turkey under different humidity regimes. The elastic properties investigated include E-L, E-R, E-T, G(LR), G(LT), G(RT), U-LR, U-LT, U-RL, U-RT, U-TL and U-TR under compression. The compression strength in all principal directions was also studied. Specimens were cut from sapwood of pine logs and sorted into four matched MC groups. Clear wood samples were conditioned at 21 degrees C and 45%, 65%, 85%, 95% RH, and subjected to compression tests. A biaxial extensometer was used to measure active and passive strain during loading. Young's modulus, shear modulus, Poisson's ratios and compression strength were calculated and compared for all orthotropic directions. The results indicate that the elastic and strength properties are significantly different in the principal directions. The Young's modulus, shear modulus and compression strength of the tested samples were strongly affected by moisture content. These properties exhibit a linear decrease with increasing moisture content. Poisson's ratios are not sensitive to MC changes.