The rate and extent of formaldehyde emission from particleboard as well as physical and mechanical properties are influenced by a large number of parameters including mole ratio of formaldehyde/urea, resin level, catalyst level and Some important factors on the formaldehyde emission of the particleboard as well as technological properties are hardener type, urea usage, and conditioning period of the particleboard. The effects of these factors on the formaldehyde emission, thickness swelling, mechanical properties, and surface quality of the particleboard have not been extensively investigated in the literature. The objective of this study was to investigate the effects of hardener type, urea usage and conditioning period on the quality properties of three layer particleboards. The process conditions of particleboard having low formaldehyde emission and high technological properties were determined from manufacturing process variables.