Isora a natural fibre obtained from Helicteres isora plant is used for reinforcement of rubber composites. The fibre is separated from the bark of the plant by a retting process. Composites were prepared using chopped untreated and alkali treated isora fibre of lengths 10 mm at different fibre loadings in natural rubber (NR) using both low temperature curing accelerators (ZDC/xanthates) and conventional accelerators (CBS/TMTD). The bonding between the fibre and rubber was improved by the use of RF resin. Cure characteristics of the composites heated to various temperatures were studied. The mechanical properties of the composites prepared using a conventional system were compared with those of the composite prepared using xanthates, at different temperatures from 80 degree C-140 degree C. Composites with the convensitonal accelerator system were vulcanised at 150 degree C. The results showed that the xanthates were effective in low temperature curing of NR and the composite vulcanised at 100 degree C showed optimum properties. At high temperature, fibre and rubber showed a tendency to degrade and hence a decrease iin properties. Alkali treated fibre composites showed enhancement of mechanical properties in both systems. Properties are improved by the use of bonding agent. The tensile fractured surface has been investigated by SEM studies and the failure mechanism has been explained. THe swelling behaviour of these composites were also studied in toluene and it was found that low temperature cured composites restrict swelling considerably.