The study was aimed at evaluating the growth behaviour of selected existing rubber clones under forest plantation management to produce timber. The clones were initially developed under intensive agricultural system to produce latex. We observed growth performance of seven-year-old rubber plantations at Bukit Hari Forest Reserve and Sungai Buloh Forest Reserve, Selangor. In both sites clone PB 235 had the greatest height and diameter. All clones performed better under lower density (600 trees/ha) plantation compared with the higher density (900 trees/ha). Effect of clones was significant in individual as well as in the combined analyses. Interaction between clone and site was highly significant but all clones maintained the same ranking across sites. Clone by density interaction was not significant and coefficients of variation of clonal materials were lower than clonal seedlings.