The effect of steaming treatment on the dynamic modulus of oak wood (Quercus castaneifolia, C. A. Mey.; Fagaceae) containing a water resistant glue-finger joint was investigated. Sample joints were made with two different types of waterproof adhesives, polyurethane (PU) and epoxy, and the samples were tested by a free flexural vibration method according to flexural and longitudinal free vibration modes. Compared with the epoxy joints, the PU finger-joints retained elastic moduli closer to their initial values. In all three vibration tests, finger-jointed oak wood specimens with either glue retained their moduli of elasticity, after the steaming treatments. In the case of longitudinal-tangential (LT) vibration, some increases were observed for the evaluated elastic moduli. After steaming, the obtained dynamic values decreased. For epoxy-bonded specimens, the correlation coefficient in terms of the elastic modulus before and after steaming were weak. There were some acceptable PU-bonded specimens, but there was a considerable decrease after steaming.