Urea formaldehyde-bonded particleboard made from oil palm trunk (OPT) and rubberwood (RW) were soaked in palm oil for 24 hr before thermally treated in oven at 180°C, 200°C and 220°C. Colour changes and decay resistance against white rot fungus (Pycnoporus sanguineus) of the samples after thermal treatment were investigated. After thermal treatment, Lightness (L*) of the samples decreased and the extent of darkening increased along with increasing treatment temperature. Generally, RW samples became redder after heat treatment while OPT samples basically showed the same pattern except it became greener when treated at 220°C. Yellowing (positive b* value) was observed at milder temperature and succeeded by bluing at higher temperature. Improvement in fungal resistance was observed for both OPT and RW samples. The weight loss of the untreated OPT and RW samples were 12.97 ± 1.62% and 30.71 ± 1.75%, respectively. At 220°C, the respective weight loss of OPT and RW samples were 4.58 ± 0.44% and 5.78 ± 1.23%. RW showed lower fungal resistance compared to that of the OPT. Strong correlations (R2 > 0.75) were found between weight loss and ΔE* suggested that fungal resistance increased along with increasing ΔE* values.