In this work, sawdust, a by-product of the wood industry, was subjected to conventional pyrolysis experiments at different temperatures (from 300 to 600ºC) and at two particle sizes. This was carried out to determine the conditions needed to maximize the liquid fraction (the so-called wood vinegar or pyroligneous acid), and to explore its composition and determine the calorific value of the char. We aim to use this liquid fraction for wood preservation on boards produced in the wood industrial sector and achieve an integral valorisation of the main obtained fractions. Maximum yield of approximately 55% by weight of wood vinegar was obtained without appreciable influence of particle size or temperature between 400 and 600ºC. Organic acids and the complex composition of the heterogeneous liquid fraction could be responsible for the preservative action. Although the percentage of solid fraction decreases as the pyrolysis temperature increases, its calorific value increases with respect to the original sawdust. Calorific values of 27.6 to 30.23 MJ/kg were obtained between 400ºC and 600ºC, similar to that of bituminous coal, which would justify the use of the solid fraction for energy.