Amazon wild germplasm (from Rondonia, Acre and Moto-Gorsso) and cultivars of Hevea brasiliensis were determined in terms of esterase isozyme. 17 bands of esterase isozyme were found, of which band 9 was common and bands 1, 2 & 4 fundamental. The germplasms from various areas disclosed a highly significant relation with the cultivars in zymogram and the zymogram types of bands 1, 2, 4 & 9 made up 69;of the total. It is therefore believed that the wild germplasms and the cultivars all originated from a forefather, and the origin of this species would possibly display bands 1, 2, 4 & 9 estarase isozyme. The germplasms from Acre and Moto - Grosso showed more variation types than others, implying that they are promising materials for breeding and selecttion programme.