Thesis shows how to improve dimensional stability of high density particleboards. Many types of single layer particleboards were produced. Resintype (UF, MUF, MF), resin content (15 %, 20 % and 25 %), board density (861- 1030 kg/m?) and board thickness (5.3 - 19.8 mm) were variable factors. Pressing temperature ( 180 °C) and pressing time (7 min.) were constant. Particleboards were investigated for dimensional stability (thickness swelling) acording to the SIST EN 317 standard. Panels were tested for their mechanical properties including modulus of elasticity and bending strength acording to the SIST EN 310 standard. Overal results show resin content and resin type used in particleboards have a great influence on particleboard properties. Dimensional stability was improved as the resin content increased from 15 % to 20 %. Where MUF and MF resin were used the thickness swelling was reduced. Melamine formaldehyde resin proved to be very effective in reducing thickness swelling of particleboards. The use of UF resin type and resin content 15 % causes minimum thickness swelling if the density of particleboards is reduced and thickness increased; some other features like bending strength diminish, and water absorption augments.