JDF-L1 is a microporous layered titanosilicate. JDF-L1-based composite materials have been prepared by melt compounding commercial polysulfone together with swollen JDF-L1 at a temperature gradient of 303-340 C. During the melt compounding process most of the swollen JDF-L1 was exfoliated, confirmed by thermal, TEM, and XRD analyses. The exfoliated JDF-L1/polysulfone master batch was diluted in polysulfone to obtain mixed matrix membranes (MMMs) with inorganic loadings in the 0-9.5 wt % range, in which exfoliated JDF-L1 particles were well dispersed. The MMMs were applied to the separation of a H 2/CH4 mixture with an improved performance as compared to the pure polymer or to chemically exfoliated JDF-L1/polysulfone membranes. The best performance obtained in this work corresponds to an 8.3 wt % MMM with H2 permeability and H2/CH4 selectivity of 12.5 Barrer and 128, respectively.