The present study aimed to evaluate the modifications of the properties of Eucalyptus cloeziana and E. grandis wood modified under hydrothermal conditions and freezing. Five trees for each species with 20 years old were sampled, and the first 3 m log was sampled from each tree. For each species, 24 specimens of dimensions 2.0 x 2.0 x 30.0 cm were prepared near the bark and close to the pith, totaling 48 specimens. Testes of dynamic flexion, colorimetry and infrared spectroscopy by attenuated total reflectance were performed. The heat treatment methods employed did not impair the mechanical properties of the wood and did not affect their apparent specific mass. The heat treatment in water implied in greater variations of the chemical properties. Possibly, these variation contributed to the color change of the wood.