Permeability coefficients of D- and L-tryptophan (D-, L-Trp) were estimated for poly(L-glutamic acid) (PLG) membranes immersed in aqueous ethanol. D-tryptophan was selectively transported (the maximum permeability ratio was 2.6) depending on the amount and the species of crosslinking agent, and on the composition of immersing solvent. It is suggested that hydrogen bonding between uncharged permeates and carboxyl and/or amide groups of PLG is an essential factor for the selective transport.