The present study reports the formulation of soy protein nanoparticles and its conjugation to antivenom. The conditions for nanoparticle formation were optimised by considering particle size, count rate, stability and zeta potential. The smallest particle size of 70.9+/-0.9 nm with a zeta potential of -28.0+/-1.4 mV was obtained at pH 6.2, with NaOH 5.4 % and 28 mu g/mg glutaraldehyde. The nanoparticle was conjugated with antisnake venom immunoglobulins (F(ab')(2) fragments) using 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide. TEM analysis indicated the increased size of particle to 600 nm after conjugation to antivenom. Further, in vitro studies indicated that conjugated antibodies inhibited the activity of protease, phospholipase and hyaluronidase enzymes of Bungarus caeruleus venom more efficiently than the free antivenom. This is the first report on the use of protein nanoparticles for conjugating snake venom antibodies and their implications for neutralising snake venom enzymes with increased efficiency.