Slug rise velocities can be measured using video imaging techniques. A video camera with a resolution of 1/30 of a second was used in conjunction with a personal computer and an image grabbing board to determine the time varying position of slugs as they travelled up a vertical fluid bed. Data was gathered for five different bed diameters ranging from 2.54 to 8.89 cm with a minimum of 3 different fluidizing velocities per tube. The bed material consisted of 3.18 mm nylon spheres which are considered type D particles using the Geldart particle classification system (1986). It was seen from the data that coherent slugs rise at a near constant velocity over the length of the bed. Influence of the tube diameter and fluidizing velocity is examined.