This paper reports the experimental finding relating to fluidization characteristics of homogenous well-mixed ternary mixtures of three different particle size at varying compositions. The study has been carried out in an un-promoted as well as a rod-promoted square bed. The bed voidage, fixed bed pressure drop and the minimum fluidization velocity have been obtained for both the above-mentioned beds. The dependence of these quantities on average particle diameter and mass fraction of the fines in the mixture for both types of beds has been discussed. The bed voidage and minimum fluidization velocity have been found to decrease with increase in the mass fraction of fines in the mixture. The experimental values of fixed bed pressure drop have been compared with those predicted from equations available in literature. The Kozney-Carman equation has been found to be significant in the present case. The experimental values of minimum fluidization velocity have been compared with the respective values calculated from the correlations proposed by earlier investigations for mono-size and binary mixture of particles using the Sauter mean diameter for the particle size. The values for minimum fluidization velocity calculated from the equation of Wen and Yu have been found to be close to the experimental values. (C) 2008 Elsevier B.V. All rights reserved.