The effect of temperature on fluidized bed flow regimes and wall-to-bed heat transfer is studied. Particles diameter ranging from 0.6 mm to 3.57 mm and bed temperature between 300 K and 1050 K are examined. Four regimes are identified and the variation of the slugging regime with temperature and particle diameter is discussed. Experimental results about temperature profile near a water cooled wall in both gas and solid phases are given as a function of flow regimes. The data are used in order to propose an heat transfer model. Two hypothesis: temperature variation in the solid phase and no temperature change are compared.