Cavitation remains a major problem in the design and operation of pumps. This paper describes the experimental investigation of cavitation on a radial flow pump which develops 21 m of head at 26 Ips of discharge at its best efficiency point (BEP) of discharge while operating at a speed of 1500 rpm. Cavitation tests were conducted at constant values of speed and discharge by varying the water level in the suction sump. Experimental results provided a clear understanding of the onset/cessation and development/reduction of cavitation while the water level in the sump was decreased/increased. The difference forthese two operations is termed as 'Cavitation Hysteresis' in a radial flow pump. Further, the effect of change of discharge on the critical value of NPSH (Net positive suction head) determined by visual inspection and by various percentage head drop conditions are presented and analyzed.