A rapid, accurate, and inexpensive quantitative HPTLC/densitometry procedure was developed for the simultaneous determination of the four major alkaloids found in the bark of Cinchona species: quinine, quinidine, cinchonine, and cinchonidine. Linearity and % recovery of the procedure were good. This procedure was applied to the analysis of bark samples from seven Cinchona species found in the DENR Cinchona Reforestation Project located in Mt. Kitanglad, Bukidnon: C. calisaya, C. hybrida, C. kartamanah, C. ledgeriana, C. officinalis, C. succirubra, and C. tjinjiroena. The species with the highest % quinine yield were C. ledgeriana, C. officinalis, and C. tjinjiroena.