The Philippine Cinchona Reforestation Project, which is located on a 1,854 ha forest on the southern slopes of Mt. Kitanglad, Bukidnon, contains an estimated 2.5 million Cinchona trees divided into seven species. Analysis was carried out for four of the major Cinchona alkaloids--quinine, quinidine, cinchonine, and cinchonidine-using High Performance Thin Layer Chromatography (HPTLC). From the results of the analyses of the wet and dry season samples, the following conclusions can be made: (1) the leaves are not a viable source of any alkaloid; (2) quinine is the major alkaloid present in the bark in all the Cinchona species tested. Quinidine, the other alkaloid with potential market value, is present in only minor amounts; (3) there is no significant difference in % alkaloid yield between the wet and dry seasons as far as the available data indicate; (4) the species with the highest % quinine content in the bark are C. ledgeriana, C. tjinjiroena, and C. officinalis. The species with the highest % quinine in the bark is C. ledgeriana which contains 6% quinine at seven years of age; (5) using the results of a study conducted by C. Serna of the quinine yield of the three species at seven years of age can be estimated as follows: C. ledgeriana - 204 kg/ha; C. officinalis - 80 kg/ha; C. tjinjiroena - 100 kg/ha. Based on these calculations, C. ledgeriana is the most promising species in terms of absolute quinine yield; (6) important additional information will be needed on the characteristics of the species such as growth performance with age, diseases, need for treatment or fertilization, pest infestation, method of debarking; (7) the large scale extraction and purification of quinine appears to be fairly straight-forward.Based on the conclusions, the following are recommended for further study and implementation: (1) the necessary agreements be made with DENR regarding the commercial use of the Cinchona plantation. This should include appropriate incentives to the DENR personnel; (2) a detailed re-inventory of the Cinchona plantation should be done in order to gather details on the distribution of the trees according to species, age, location, and their condition; (3) two pilot plants should be set up; a pilot plant for bark processing at the plantation site and a chemical extraction pilot plant for the purification of quinine. Purification of the minor alkaloids (quinidine) can also be considered, and; (4) a study on the breeding and propagation of the high-yielding Cinchona trees (C. ledgeriana, C. officinalis, and C. tjinjiroena) should be initiated.