Poly(vinylidene fluoride) (PVdF) and polyaniline (PAni) were partially sulfonated, using chlorosulfonic acid (CSA) as the sulfonating agent. The prepared partially sulfonated PVdF (SPVdF), having a degree of sulfonation ~22%, and the partially sulfonated PAni (SPAni), having a degree of sulfonation ~29%, were blended at constituent wt% ratios of SPVdF:SPAni = 95:5, 90:10, 85:15 and 80:20 in order to fabricate different blend membranes. These blend membranes exhibited extremely low methanol uptake and methanol permeability, as well as, high membrane selectivity ratios (especially at high methanol concentrations) The blend membranes also exhibited superior water uptake capacity, water swellability, ion-exchange capacity and proton conductivity, compared to the pristine PVdF and SPVdF membranes. The SPVdF:SPAni (80:20) blend membrane was found to produce the best results in terms of exhibiting the lowest methanol permeability values of 1.50×10-9 cm2s-1 (at 2 M methanol) and 6.30×10-9 cm2s-1 (at 8 M methanol), and the highest membrane selectivity values of 3.27×106 Sscm-3 (at 2 M methanol) and 7.78×105 Sscm-3 (at 8 M methanol). On the other hand, introduction of Nafion within the SPVdF/SPAni blend membrane, to form a ternary blend membrane (i.e. SPVdF:Nafion:SPAni = 50:30:20), resulted in much improved ion-exchange capacity and proton conductivity.