Technical Abstract: Non-uniform heating of fresh fruits caused by variations in radio frequency (RF) fields is a major obstacle in developing postharvest insect control treatments based on RF energy. A fruit mover was developed to evaluate possibilities to improve RF heating uniformity of large fruits, such as oranges and apples, in a 12 kW batch type RF system. This fruit mover provided a means to rotate and move fruits in water when subjected to RF heating. Parameters for moving and rotating of fruits in the developed mover were selected based on consideration of vortex formation, foaming, damage to the fruits, and volume occupied by fruits in water. RF heating uniformity of oranges and apples in the mover was assessed using an infra-red imaging technique and a direct temperature measurement with fiber-optic sensors and thermocouples. The results showed that, with rotation and movement of fruits, temperature uniformity in oranges and apples was greatly improved with less than 2.8°C and 3.1°C standard deviations, respectively, after an average temperature rise of about 30°C in 7.8 min. The fruit mover can be used to develop a treatment protocol for disinfesting fresh fruits and to simulate industrial scale and continuous treatment systems.