A novel system has been developed to control granule growth in a high sheer (speed) granulation. The system basically consisted of an image processing and a fuzzy control system. An image probe composed of a CCD camera, air purge unit and high energy xenon (Xe) lightning system was also developed to continuously take granule images through the sidewall of the vessel. The images were digitized by the image processing system and granule median diameter and shape factor were calculated automatically. Median diameter and shape factor of granules sampled out during granulation were also calculated by manually, and then compared with the automatically computed ones. Close agreement between both measurements was obtained, showing the developed system could continuously monitor granule growth during high shear granulation. A fuzzy control system using a linguistic algorithm employing if-then rules with a process lag element taken into consideration was developed to control granule growth accurately without any excessive growth (overshoot). This newly developed system was applied to actual high shear granulation of pharmaceutical powders and validity of the system was investigated it was found that the system could control granule growth with high accuracy, regardless of changes in operating conditions.