Seventy nine IAA producing rhizobacteria, isolated and selected from rubber plans, were screened to identity efficient isolates under polybag conditions. The IAA production of the isolates in sucrose minimal salts medium was in the range of 0.48-62.84 Meug mL-1. Ten mL of each culture containing 10 8 cfu mL was inculated to the rubber seedlings in three splits at monthly intervals from transplanting of the germinated seedlings to the polybags along with uninoculated control plants. after six months growth, the plants were uprooted and mesured various growth parameters. Out of the 79 isolates evaluated, 12 isolates showing more growth improvement of the seedlings were selected. They were the medium IAA producers (in the range of 4.08- 25.46 meug mL-1). All these isolates showed phosphate solubilising efficiency in A patite agar medium. They solubilised Ca3 (PO4)2 and AIPO4. FePO4 solubilisation was shown by 10 isolates and was less than the other two sources of phosphates. Three isolates viz RB 88, Ri 25 and RH 104 showed the solubilisation of Raj phose, the sparingly soluble from of fertilizer. Eleven isolates showed medium to high levels of ammonia production and low to medium levels of phosphatase activity. Nine isolates showed low to high levels of siderophore production. All the isolates showed antagonistic activity against at least one of the five major rubber pathogens tested in dual culturing. The study showed that the top ten IAA producers were not included amoung the 12 selected isolates. The study suggests that a compination of different mechanisms, other than IAA production along, may be involved in regulating and optimising the plant promoting effects of root colonizing bacteria, the role of which under field conditions is to be further investigated.