Poly(ether ether ketone) (PEEK) is one of the mostattractive polymers for organic solvent resistance applications because ofits high thermal and organic solvent resistance. However, one of the maindisadvantages is that PEEK has to be processed by using harsh solvents,such as methanesulfonic and sulfuric acid. Here, we report for thefirsttime the preparation of PEEK membranes for organic solventfiltration byusing common organic solvents. The preparation method consists of theconversion of PEEK into a soluble precursor, followed by dissolution in amixture of tetrahydrofuran andN,N-dimethylacetamide. The resultingsolution is used to obtain the membranes by phase inversion. In thesecond step, we convert the PEEK precursor to PEEK by treating theobtained membranes with an aqueous acid solution. The resulting PEEKmembranes have good permeance and rejection, along with high stabilityin organic solvents and at high temperatures (up to 140°C). This procedure opens many possibilities for processing PEEK intomembranes by using common techniques to obtainflat sheet membranes or hollowfibers for a broad range of applications.