The purpose of this study was to determine the behavior of LOSP on the bending strength of glulam manufactured using Malaysian tropical timber namely Mengkulang. Timber preservatives are used to prevent from degradation which can be due to some extend weathering, fungi, or insects. Therefore, the use of quality preservatives is essential in determining the performance of timber under such conditions. An experiment was carried out to determine the effect of using preservative to the performance of Mengkulang (Heritiera spp.) glued laminated timber (glulam) treated using light organic solvent preservative (LOSP). LOSP was chosen due to its more environmental friendly chemical ingredient. Ten specimens of Mengkulang manufactured at a factory in Selangor, Malaysia which followed the Malaysian Standard, MS 758 were divided into one group of five timber beams treated with LOSP prior to gluing and another group of five untreated timber beams. This paper only reported the effect of LOSP on the bending strength properties. The static bending test under four-point loading was carried out based on American Standard for Testing and Material, ASTM D 198. The results showed that LOSP-treated Mengkulang glulam had higher values of modulus of rupture (MOR) and modulus of elasticity (MOE) compared with untreated Mengkulang glulam by 4 % and 6 %, respectively. Since most researches have so far focused on temperate softwood species, the findings of this study are significant as the specimens were from tropical timber species and the study employed experimental