The use of maleic anhydride (MAH) modified and unmodified natural and synthetic trans-1.4-isoprene rubber (TIR Gutta Percha and TIR Synthetic) as hot-melt adhesives for plywood manufacturing under various glue spread levels was investigated and their gluability and durability in accordance to SNI 01-5008.2-99 standard were evaluated. TIR modified with MAH (MTIR) either natural (MTIR Gutta Percha) or synthetic (MTIR Synthetic) adhesives could reveal a satisfactory waterproof gluability. This is considered to be due to an enhanced adhesion caused by an occurrence of esterification between the hydroxyl groups of wood and the acid anhydride groups of MTIR during hot pressing. Infra red spectroscopic analysis showed both TIR Gutta Percha and TIR Synthetic have almost similar spectra. In the spectra of MTIR`s after purification, the peak at 1724 and at 1716 cm-1, respectively for MTIR Synthetic and MTIR Gutta Percha existed, indicated the characteristic for C=O of MAH. Differential thermal analysis showed that before and after modified with MAH, the melting and decomposition temperatures of MTIR Gutta Percha and MTIR Synthetic adhesives were quite different from TIR Gutta Percha and TIR Synthetic adhesives indicated that chemical modification of TIR`s with MAH were occurred. Either MTIR Gutta Percha or MTIR Synthetic adhesives are very appropriate for wood as hot melt adhesives.