In this study, hornbeam (Carpinus betulus L.), poplar (Populus deltoides), chestnut (Castanea sativa Mill.) and Uludag fir (Abies bommulleriana Motif.) were heat treated at 212 degrees C for 1 hour and 2 hours by the ThermoWood((R)) method. Colour and glossiness were determined and compared with untreated samples. Results showed that lightness (L *) decreased for all tested samples and that the decrease was higher with more intense treatments. Colour parameter a* (red/green) initially increased with heat treatment, then decreasing afterwards. The colour parameter b* (yellow/blue) on the other hand, decreased for Hornbeam and Chestnut and increased for Poplar and Uludag fir. Generally, the glossiness decreased with heat treatment for both measurements, along and across the grain. All factors and interactions were found to be significant (according to alpha = 0.05) with the exception of interaction (AB) for parallel (//) glossiness in 60 degrees. The highest total colour change was achieved for Hornbeam (Delta E*= 41.58).