Qualitative effects of temperature and height from the distributor plate on the transition velocity to turbulent flow regime(U_c) have been measured in a gas fluidized bed(0.1 m i.d. and 2.1 m height) using sand as bed material. Bed temperature(15-500 ℃), height from the distributor plate(0.02-0.10, 0.10-0.15, 0.15-0.24, 0.24-0.29, 0.02-1.97 m), and mean particle size(0.134, 0.256 mm) were considered as experimental variables. The transition velocity to turbulent flow regime increased with increasing bed temperature, however, decreased with increasing height from the distributor plate. The previous correlations on transition velocity to turbulent flow regime compared with the measured values. Most correlations reported in the literature appeared inadequate to determine the effects of temperature and height from the distributor plate on transition velocity to turbulent flow regime.