This study endeavored to document some of the fungal species affecting Philippine dipterocarps in Mt. Makiling. Collection of macroscopic fungi was conducted in five selected sites. A 1-2 km transect line was laid out per site, and four 10 x 10 m2 quadrat sampling plots were established to determine existing fungi. These fungi were quantified using ecological parameters such as density, frequency, diversity and evenness value. Twenty-seven species of macroscopic fungi belonging to fifteen genera were found associated with dipterocarps. These were characterized morphologically and anatomically prior to identification. The Ganoderma, Polystictus, Auricularia, Fomes and Polyporus species dominated the study areas. Among the dipterocarp host species, white lauan (Shorea contorta) has a wide range of fungal association. Decay capacity tests on heartwood and sapwood using inoculants were conducted in the laboratory on four dipterocarp species. Weight loss in percent, and absorbability of water in grams after 20 weeks of incubation were measured and compared. These fungi are commonly considered harmful organisms that cause great economic losses in wood. Nevertheless, they could be beneficial to the ecosystem. This permits the growth of young, vigorous trees and thereby, play an integral role in maintaining the dynamic and ever-changing nature of the forests.