Dry powder inhalers (DPIs) are fast becoming the most popular alternative to metered dose inhalers following the Montreal protocol. Besides, the regulatory requirements with the introduction of recent advancements in particle and device engineering DPIs are rapidly gaining momentum in the field of protein and vaccine delivery and also in cancer and gene therapy. An overview of particle engineering and device engineering aspects used in the design and development of DPI is reported in this article. The article also reviews the present characterisation and evaluation method used for DPIs. Keywords : DRY POWDER INHALERS, PARTICLE ENGINEERING, DEVICE ENGINEERING, EVALUATION