Application of liquid natural rubber (LNR) as a reactive plasticiser in nitrile rubber (NBR) was studied using compounds containing different loadings of dibutyl phthalate (DBP) and LNR. Cure characteristics, physical properties as well as ageing and ozone resistance were measured on compounds containing the plasticisers upto 15 phr. Changes in rheological behaviour, imprated by the plasticiser on NBR, were evaluated using four compounds containing 5, 10, 15 and 20 phr of plasticiser. The study showed that LNR can be used as a plasticiser in NBR without affecting its cure characteristics, storage life and most of the physical properties except brittle point. Improvement was observed in properties like green strength, mill shrinkage and compression set. Rheological studies showed that LNR system at high temperatures and shear rates have lower viscosity than the corresponding DBP systems which enables easier moulding. Die swell also decreased with the incorporation of LNR. The use of LNR as a reactive plasticiser was justified by the higher volume swell in oil indicative of its ability to compensate for the shrinkage resulting from leaching.