The relationships of the surface morphologies to the surface chemical compositions in poly(ethylene oxide)-segmented nylon (PEO-Ny) membranes prepared by the phase-inversion method were studied using scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), and static secondary ion mass spectrometry (SSIMS). The PEG-Ny's used were high semicrystalline PEO-segmented polyiminosebacoyliminohexamethylene (PEO-Ny610), low semicrystalline PEO-segmented poly(iminosebacoylimino-m-xylylene) (PEO-NyM10), and amorphous PEO-segmented poly(iminoisophthaloyliminomethylene-1,3-cyclohexylenemethylene) (PEO-NyBI). SEM observation showed that the surfaces of the PEO-Ny610 and PEO-NyM10 membranes were composed of crystalline spherulite and that the PEO-NyBI membrane surface had a nodular structure. ESCA analysis exhibited the enrichment of the PEO segment at the surfaces of the PEO-Ny610 and PEO-NyM10 membranes. On the other hand, the enrichment of the Ny segment was observed in the case of the PEO-NyBI membrane. SSIMS analysis revealed that the outermost surfaces of the PEO-Ny membranes except the PEO-NyBI membrane were almost covered with the PEO segment.