The aim of this study was to investigate the effect of operating variables on the continuous rotary drum granulation of fertilizers. The fertilizers, viz. urea and potassium chloride with bentonite as a binder, were taken as feed materials. The effects of moisture content and feed rate on continuous rotary drum granulation are discussed. Step response experiments with respect to the above two variables were also conducted to investigate the dynamic behaviour of the system, which will be of use in the control of the granulator.