This paper presents a study of particle residence time near the walls of gas fluidized beds by DEM simulation. The simulation experiments were performed in two beds, one of 50 mm x 50 mm cross-section and the other of 90 mm x 90 mm cross-section. The particles used were 0.5 and 1 mm. in diameter and 2650 kg/m(3) in density. The number of particles used was 600,000 and 500,000 for simulations of the 0.5 and 1 mm diameter particles, respectively. The advantage of this approach is that it enables an unprecedented amount of information pertaining to the motion of individual particles near the walls of a fluidized bed to be obtained. These include the distribution of particle residence time, mean residence time, contact frequency, and contact distance at the walls. Variations of particle residence time with particle size, gas velocity, and wall position are examined. Significance of the results to modelling of particle-to-wall heat transfer in fluidized beds is highlighted.