A disorder causing the cracking of bark in the lower trunk region of seedlings and in the root stock of bud-grafted trees of Hevea brasiliensis was observed recently. A preliminary investigation was carried out for the first time to study the occurrence, symptoms, its relationship to the genotype of clones or seedlings, age and growth of trees. The observations were that, this disorder appears only after abour three years of establishment and reaches a high percentage in about seven years and is completely absent in bud wood nurseries. Bud-grafted trees with the disorder had a greater girth than those unaffected. The genotype of the scion in bud-grafted trees did not have a significant influence on the occurrence of this disorder. The nature and the symptoms of this disorder do not show the involvement of a pathogen of, but secondary infections may be the reason for bark decay around cracks. The information gathered so far points to an inherited physiological disorder that appears at maturity affecting both root stocks in bud-grafted trees and the lower trunk region in seedlings.