Compositions comprising an RNA interference (RNAi) compound complexed to or encapsulated by lipid particles are provided. The lipid particle is a lipid nanoparticle, a liposome or a combination thereof. The lipid particle comprises a cationic lipid, a phospholipid, a sterol or a tocopherol or a derivative thereof, and a conjugated lipid. The invention also provides methods for treating pulmonary diseases or disorders such as pulmonary fibrosis and sarcoidosis using the compositions comprising the RNAi-lipid particles of the invention. The methods comprise administering one or more of the RNAi compositions to the lungs of the patient in need thereof via an inhalation delivery device, for example, a nebulizer, dry powder inhaler, or a metered dose inhaler.
