Some smoothly fluidized binary mixtures exhibit no tendency to segregate under a particular combination of solids and fluid volume fractions. In these cases the equilibrium mixture remains stable, even in the absence of mixing forces. The conditions corresponding to segregation potential free mixtures can be theoretically predicted from the physical properties of the system, and have been validated for liquid fluidized systems. This paper shows that the same approach may be applied to gas fluidized beds of fine particles. Experimental results of different binary mixtures in gas fluidized beds are reported to support the theory.