Idiopathic pulmonary fibrosis (IPF) is a fatal disease with a median survival of 3-4 years after diagnosis. It is the most frequent form of a group of interstitial pneumonias of unknown etiology. Current available therapies prevent deterioration of lung function but no therapy has shown to improve survival. Periostin is a matricellular protein of the fasciclin 1 family. There is increased deposition of periostin in lung fibrotic tissues. Here we evaluated whether small interfering RNA or antisense oligonucleotide against periostin inhibits lung fibrosis by direct administration into the lung by intranasal route. Pulmonary fibrosis was induced with bleomycin and RNA therapeutics was administered during both acute and chronic phases of the disease. The levels of periostin and transforming growth factor-β1 in airway fluid and lung tissue, the deposition of collagen in lung tissue and the lung fibrosis score were significantly reduced in mice treated with siRNA and antisense against periostin compared to control mice. These findings suggest that direct administration of siRNA or antisense oligonucleotides against periostin into the lungs is a promising alternative therapeutic approach for the management of pulmonary fibrosis.