The mixing behavior of light paper pellets in a sand fluidized bed is investigated for varying proportions of paper pellets (0-20 mass%) over a range of superficial air velocities (0-1.5 m/s) at ambient conditions. It is found that a fluidization number greater than 2 is essential to achieve good mixing as long as the proportion of paper pellets in the bed is up to about 10 mass%. For 20 mass% of paper pellets in the bed, mixing did not occur and paper pellets preferentially collected in layers. Bed voidage and minimum fluidization velocities for mixed beds of sand and paper pellets are reported. These studies provide the supporting data needed for the co-combustion of paper pellets in a hot-sand, fluidized bed.