The catalytic properties of nanosized copper structures are the subject of many reports. In this study, the catalytic activity of copper nanotubes (NTs) in a PET matrix of track-etched membranes (TMs) in the flow mode and under stirring in the static mode is studied using the example of the classical p-nitrophenol (p-NP) reduction reaction. Composite TMs are prepared by the electroless template synthesis ; after 40 min of deposition, the inner diameter of the copper NTs is 295.4 nm, while the wall thickness does not exceed 47.5 +/- 4 nm. The structure and composition of the synthesized composite membranes is studied by gas permeability, electron microscopy, energy dispersive analysis, and X-ray diffraction methods. It is shown that, in the flow screening mode, the composite catalyst provides a high p-NP reduction reaction rate; however, after the third test run, the reaction rate decreases by 97%; further, the composite is almost inert. In the static mode, at a relatively low reaction rate, the copper NT-based catalyst provides a high p-NP conversion and remains active for at least six consecutive test runs without any additional activation and regeneration. The results show that composite catalysts based on PET TMs and chemically deposited copper NTs are highly promising.