The inhibitory effect of lemon grass oil on the growth of mould Aspergillus niger and bacteria such as Basillus subtilis and Pseudomonas aeruginosa was evaluated. Preservative action of lemon grass oil was also evaluated for several food grains viz.wheat, millet, barley and green gram. Within a storage period of fifteen days, samples of wheat, millet and barley treated with lemon grass oil showed no physical deterioration. Off colour,off odour and mouldiness however characterized treated green gram and untreated (control) samples of wheat, millet and barley.