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Polymer brushes are nanoscopically thin, covalently bound coatings that display interesting properties such as low fouling and stimuli-responsiveness. To enable successful implementation of brushes as functional coatings, their stability is key. Although the solvent stability of brushes has been investigated to a certain extent, not much is known about the stability of brushes subjected to electric fields. With the growing interest in polymer brushes for battery and sensor technology – there is a growing knowledge gap on the stability of polymer brushes in the presence of an electric field. In this study, we compared the solvent and electro-stability of different polymer brushes and brush-anchor combinations. We grafted neutral, positively, and negatively charged brushes from thiol-based and diazonium-based anchors on gold electrodes. In this work, we show that the causes of chain degrafting differ in absence and presence of an electric field. Without an electric field, stability is increased, in particular, by favorable polymer–polymer interactions, stable monomers, and mild solvent conditions. However, electro-stability is greatly improved by the use of noncharged polymers or short polyelectrolyte chain lengths and using potentials in the operating window, which is determined by the polymer and anchor redox reactions. Furthermore, we observed a chain-length dependence for the degrafting of polyelectrolyte brushes under repulsive fields, whereas neutral poly(MeOEGMA) brushes remained comparatively stable between −0.8 and +0.8 V. Understanding how these parameters affect the stability of polymer brushes helps in the design of new, stable polymer brushes for use in electrochemical systems.