Modified poly(phenylene oxide) membranes were used to separate methanol from methyl tert-butyl ether solutions through a pervaporation process. The process characterization was performed considering the influence of both the permeate side pressure and the methanol concentration in the feed mixture. The membrane performance has been expressed in terms of transmembrane flux and overall separation factor. Experimental results are discussed in terms of solubility, diffusivity and driving force for the diffusion process of each component through the polymeric membrane.