Mixed matrix membranes (MMMs) are composites of highly selective fillers within a polymeric matrix, resulting in higher selectivity and/or flux in gas separation applications. In this work, micron sized MIL-101 crystals with potential of gas separation by adsorption were synthesized and used as filler for the preparation of MMMs for gas separation. Gas adsorption measurements were performed for CO2, CH4 and N2 using MIL-101 crystals and the results showed significant adsorption of CO2 compared with the two other gases at different pressures. SEM images and XRD analysis were used to characterize the filler particles and the synthesized membranes. MIL-101/Matrimid MMMs were synthesized with up to 30 wt.% loading of filler particles. SEM images showed good dispersion of the particles in the polymeric matrix and also good adhesion between the filler particles and the polymer. Permeability measurements were performed for pure gases of CO2, CH4 and N2 and the results showed improved CO2/CH4 and CO2/N2 ideal selectivities for the MMMs compared with those for the neat Matrimid membrane. For the MMMs with 10 wt.% loading, permeability of CO2 was found as 6.95 Barrer and ideal selectivities for CO2/CH4 and CO2/N2 were as 55.77 and 52.92, respectively.