Abstract: Mycorrhizae are symbiotic association between specialized soil fungi and plants. Trees of Dipterocarpaceae have long been known for their ability to associate with ectomycorrhizal (ECM) fungi. Apart from modifying the lateral root system of their host, ECM fungi benefit their host plant in many ways, such as: protecting against root pathogens, providing mineral nutrients, increasing drought tolerance and enhancing seeding growth in the nursery. In this study, DNA from ectomycorrhizal roots was successfully amplified from 15 species in 6 genera of regular type. These included Anisoptera (1 species), Cotylelobium (1 species), Dipterocarpus (5 species), Hopea (3 species), Parashorea (1 species) and Shorea (5 species). Molecular techniques were used to identify the ECM. ITS (internal transcribed spacer) fragments located between the 18 S and 28 S rRNA genes in the nuclear genome were amplified and sequenced. The sequences of ITS were compared with sequences in the GenBank. The results revealed that the 33 mycobionts participating in the symbioses in ECM roots were in 8 families including Thelephoraceae (13), Russulaceae (6), Amanitaceae (1), Cortinariaceae (3), Sclerodermataceae (4), Agaricaceae (1), Pisolitaceae (3) and Boletaceae (2). The observed host specialization showed that these fungi could associate with more than one host plant species.