The need to fabricate a nanoporous sensor that can be utilized for the resistive-pulse sensing of particles without labeling them has generated extensive research and led to various methods for nanopore fabrication on several materials. Since the first development of track-etching method and its use on polymer membranes, there has been an ongoing interest in their applications. In this review, we look at the background on tracking technology, chemical etching of these tracks for the fabrication of nanopores with varying geometries and we discuss their applications as electrochemical sensors for biomolecules (i.e. DNA and protein), nanoparticles and others. The main emphasis is on resistive-pulse sensing using single nanopores fabricated by track-etching on polymer membranes. We also discuss sensing based on the specific current - potential (I-V) behavior of asymmetric nanopores as the sensing element. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.