Nanofiltration using solvent-resistant membranes has become an important separation technology. Polydimethylsiloxane and polyimide are important materials for preparation of solvent-resistant nanofiltration (SRNF) membranes. In this study, the performance of commercial polydimethylsiloxane and polyimide SRNF membranes (as a trademark of MPF and STARMEM) with molecular weight cutoff values of 200-700 Da was compared in terms of organic solvent preconditioning effect, solvent compatibility, solvent flux, and solute rejection. Organic solvents employed were methanol, toluene, ethyl acetate, dichloromethane, and acetone and the organic solutes in a molecular weight range of 160-850 Da were used. Membrane preconditioning with different organic solvents did not affect membrane performance of the polydimethylsiloxane-based MPF membranes but had a significant influence on the polyimide-based STARMEM membranes. Both MPF and STARMEM membranes are not compatible in dichloromethane. MPF membranes were inert to the organic solvents and had relatively low solvent fluxes. STARMEM membranes were highly swollen in methanol and offered much higher solvent fluxes and attractive NF performance in toluene.