The twin screw extruder has recently become popular as a continuous wet granulation technique. It is logical that granulation using a twin screw granulator will depend on several process variables including powder feed rate but little is known about how these variables will affect the kinetics and mechanisms of granule growth and the eventual structure. The work focuses on understanding how granule properties like structure, surface, strength, dissolution etc., change with varying powder feed rate and attempts to develop the science behind granule formation which ultimately allows a priori process and product design. An attempt has been made to understand the steps involved in granule formation in twin screw granulator. The granules became denser and stronger with an increase in powder feed rate. (C) 2010 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.