A new self-organization phenomenon was observed during pulse current electrodeposition of nickel layers from an acidic sulfamate electrolyte containing a few 100 mg/l of a polymeric surfactant. Scanning electron microscopy (SEM) analysis reveals ordered arrays of nanometer sized pits. Within domain of about 1 mu m size the pits arrange on a hexagonal lattice with a pore-to-pore spacing of about 120 nm. SEM inspection of cross sections show that the pits are the ends of straight nanochannels of about 40 nm diameter, extending virtually through the complete layer parallel to the growth direction. The additive is an amphiphilic polymer consisting of a backbone carrying carboxylate groups, styrene units and polyether side chains. According to current knowledge the presence of this polymer in the electrolyte and the application of special current pulse patterns are preconditions for the formation of the ordered nanopore arrays. The mechanism responsible for this kind of self-organization is still a matter of speculation but experimental results point to hydrogen nanobubbles acting as templating agents. (C) 2014 The Electrochemical Society. All rights reserved.