A gene transfer system for Hevea brasiliensis was estabilished with Agrobacterium tumefaciens GV 2260 (p35SGUSINT) and LBA4404 (pAL4404/pMON9793). In this system Hevea brasiliensis anther-derived calli were transformed with vectors harbouring the B-glucuronidase (gus) gene and the neomycin phosphotransferase (nptII) gene. The success of gene transfer was determined by histochemical staining and fluorometric assay for B-glucuronidase activity and enzyme linked immunosorbent assay for detecting neomycin phosphotransferase II protein levels. These indepedent assays all showed a several-fold increase, compared to control values, in enzyme activity and protein levels in extracts from transformed calli and embryoids of Hevea brasiliensis. The presence of the gus gene in transformed plantlets was confirmed by using the polymerase chain reaction protocol as performed on DNA isolated from transformed calli and embryoids.