Poly(vinylidene fluoride) (PVDF) based mixed matrix membranes (MMMs) comprising crystalline structures of Metal organic frameworks (MOFs), CuBTC, CuBDC, MIL-53(Al) and NH2-MIL-53(Al) were fabricated and investigated for gas separation applications. MOFs and membranes were extensively characterized by FT-IR, XRD, SEM and TGA techniques. 10 wt% loading of CuBTC in PVDF showed 43.6 and 118.7% permeability enhancement for He and CO2 gases compared to the pure membrane. Moreover, the high selectivity enhancement of 96% was observed for CO2/CH4. In regards to CuBDC, 37.5 and 117% permeability increase for He and CO2 gases was reported for 15% loading. Furthermore, the best selectivity was related to CO2/CH4 in which 109.3% increscent was achieved relative to the pure membrane. Since CuBTC and CuBDC exhibited interesting effects on CO2 transport, they can be promising additives for polymer membranes. The membranes containing 10% wt of NH2-MIL-53(Al) showed 11.25 and 22.41% selectivity enhancement for He/CH4 and CO2/CH4. However, for those membranes containing MIL-53(Al), were decreased by 3.33 and 1.33% compared to the pure PVDF membrane. The different behavior of NH2-MIL-53(Al) and MIL-53(Al) can be explained by their different surface properties related to the existence of amino groups on NH2-MIL-53(Al). (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.