A study was undertaken to determine the effect of diatomaceous earth (DE a source of Silicon) on yield and disease infestation of rice. The experiments were carried out in old alluvial zone of West Bengal during 2012 - 2013. All the treatments were performed in a completely randomized block design. Results showed a significant increase in grain yield with Si application. Highest grain yield was found in the treatment of DE @ 600 kg ha^-1 along with POP (package of practice). The POP contained FYM @ 5 t ha^-1, ZnSO₄. 7H₂O @ 25 kg ha^-1 and N: P: K :: 100:50:50 kg ha^-1. All the treatments of Si were found to have a significant effect in promoting and disease resistance while higher doses of DE had a better effect than lower one. The investigation concludes that application of diatomaceous earth @ 600 kg ha^-1 along with POP was effective to increase the grain yield of rice. Whereas, regarding reduction of pest and disease infestation DE application (@600 kg ha^-1) showed significant effect when amalgamated with half the package of practice.