We present a surfactant-controlled etching method which allows the production ofasymmetric track-etched nanopore membranes with diode-like ionic conductivity. Theasymmetry of the pores is provided by self-assembly of amphiphilic molecules atthe pore entrances on one side of the membrane during chemical etching whilethis process is excluded on the other side. By varying the alkali concentrationin the etchant, control over the pore profile is achieved. The pore geometry ischaracterized in detail using field-emission scanning electron microscopy. Themethod is equally applicable to membranes with many and with single pores andmay constitute an alternative to existing methods of production of resistive-pulsesensors.