Abstarct: Drying is an important operation in many industries such as chemical, food, mextallurgical, pharmaceutical and etc. Fluidized bed drying is considered as one of the most successful drying techniques. The advantages of fluidized bed drying can be summarized as follows: 1. High heat and mass transfer rates, because of good contact between the particles and the drying gas. 2. Uniform temperature and bulk moisture content of particles, because of intensive particle mixing in the bed. 3. Excellent temperature control and operation up to the highest temperature. Paddy is one of the grains that are needed to be dried after harvesting. In order to investigate the influences of effective parameters in fluidized bed drying of paddy rice, a laboratory scaled fluidized bed dryer designed and constructed to obtain experimental data. The fluidization column was made of Aluminum with 0.2 m inner diameter, 0.45 m height and 0.001 m wall thickness. A perforated distributor plate with 0.001 m thickness and 0.003 m holes was used to obtain uniform distribution of the fluidizing air. The air heater consists of four strip electric elements, which has 4000 W total power. The air was provided by a centrifugal blower. The temperature distribution through the bed was measured by an electronic thermometer. The pressure difference between the two sides of distributor plate and the distributor plate and fluidized bed height was measured with a differential manometer. Air velocity was measured and determined with an electric anemometer. Drying conditions were as follows: drying air temperature of 21–80 ºC, bed thickness of 0.04-0.08 m and air velocity of 0.8,185 and 2.7 m/s in fixed bed, minimum fluidization and fluidized bed situation, initial moisture content of paddy 35.21%, 38.25%, 39.07%, 43.3% , 43.92%. Experimental data shows that increasing the bed thickness cause the pressure drop of the bed to be increased. But the minimum fluidization velocity is independent from bed thickness. Also increasing the temperature of drying air allows the pressure drop and minimum fluidization velocity to be increased. According to experimental data, bed thickness, Drying air velocity, temperature of drying air and initial moisture content of paddy kernels have an important effects on the kinetics of drying. Increasing the velocity and temperature of the drying air allows the rate of heat transfer to the product to be increased. instead, the rate of drying decrease with increasing the bed thickness and intioal moisture content of kernels.