Fluidized bed technology offers an attractive way for energy production with clean environment by the combustion of even low-grade waste derived fuels (WDF). This paper reports experimental results concerning the characterization of a small-scale bubbling atmospheric fluidized bed combustor with WDF batch feeding. The combustor having 0.215 m inner diameter and 1.88 m height is equipped with a packed-bed sandwich-type fluidizing air distributor. The experimental fluidized bed combustor (EFBC) is provided with facility items necessary for the operation, control, and measurements. Results of the measured fluidized bed pressure drop and temperature were investigated for cold flow, hot flow, and combustion tests during the characterization procedure. The results of these tests clearly indicated the good fluidization characteristics inherent to well-controlled operation of the EFBC facility. The characterization tests also indicated the reproducible and safe operation characteristics of the EFBC facility without appreciable leakage of fluidizing air and exhaust gases. Moreover, the obtained uniformity of the fluidized bed temperature together with the high estimated values of bed-to-immersed cooling coil heat transfer coefficient, added more evidence on the good combustion characteristics of the investigated EFBC facility.