Technical Abstract: Fifty-two accessions of Canarium involving seven species, C. ovatum, C. album, C. megalanthum, C. harveyi, C. indicum, C. mehenbethene, and C. odontophyllum were studied for isozyme polymorphisms. Starch gel electrophoresis with a histidine-citrate buffer system (pH 6.5) was employed to assay six enzymes: LAP, MDH, GPI, PGM, TPI and UGPP. Species were polymorphic for most of the six enzyme systems assayed and the level of phenotypic polymorphism for different species and enzymes assayed ranged from 0 to 0.88, with an overall average of 0.28. The weighted average of polymorphisms across different enzyme systems for different species ranged from 0.16 for C. indicum to 0.47 for C. ovatum, with an overall average of 0.26. On average, LAP was the most polymorphic enzyme (0.43) followed by GPI (0.38), MDH (0.27), UGPP (0.26), PGM (0.18), and TPI (0.13). The complexity of isozyme phenotypes indicates that interspecific hybridization and polyploidy might have played a major role in the evolution of Canarium species. Geographic speciation in Canarium was not apparent from the phonetic analysis of the isozyme data.