The effect of board density on dimensional stability was determined using particleboards of Canelo (Drimys Winteri Forst.) with densities between 550 kg/m3 and 750 kg/m3 . The boards were subjected to relative air humidities between 46% and 85% at 20 °C. Thickness and longitudinal expansion was determined; the thickness expansion was 34 times greater than the longitudinal expansion. A variation of 1% in air humidity produced a thickness expansion that increased from 0.914% to 1.195% when board densities changed from 550 kg/m3 to 700 kg/m3. For the same density variation, a change in linear expansion from 0.027% to 0.37% was determined. Equilibrium moisture content was also determined, and was found to increase as the board density decreased.