Quantitative differences in the number of primary xylem points, number of intraxylary phloem points and the thickness of xylem and phloem in one year old twigs were assessed in eight clones of Hevea brasiliensis. The linear relationship of these structural characteristics on the growth characteristics such as diameter of the twigs of the tapping trees and girth increment on tapping were also examined. The data revealed marked differences of anatomical and growth chracters among clones. The number of intraxylary phloem points had significant association with the number of primary xylem points (r=0.8158**), twig diameter(r=0.4231*). The number of primary xylem points also was correlated with the twig diameter (r=0.5258**). This trait also showed a positive relationship with the rate of girth increment on tapping though not significant.