RRI Vietnam started this hand pollination programme in 1982. A total of 161 selected clones derived from the 1982-83 programme were introduced in small-scale clone trials (SSCT). The control clones were GT1, RRIM 600 and PB 235. The clones that had vigour and production better than GT1 and RRIM 600 were introduced into large-scale clone trials (LSCT) from 1990 in different localities prior to recommendation. The yield of the nine top clones for the first four years of tapping in the SSCT ranged between 90;and 138;compared to PB 235 or between 124;and 189;compared to RRIM 600. The performance of these clones was also observed in other SSCTs. As their good growth has been maintained in LSCT, it is hoped that their high yields might also be maintained. Studies on their latex physiological characteristics showed that under suitable tapping systems, the yield potential of some of the selected clones could be increased. The parents of the proven clones were PB 235, RRIC 110, RRIC 117, RRIC 121, RRIC 123, RRIC 104 and IR 45. Crossing patterns were W x W, W x WA and WA x WA.