Biodurability of nanomaterials (NMs) through dissolution and enzymatic biodegradation or chemical disintegration is an important property that needs to be investigated for their potential to cause harm to humans and the environment. NMs may therefore be differentiated based on their biodurability between those that are amenable and those that are resistant to dissolution, biodegradation and/or disintegration. This document compiles the relevant information on the biodurability of the pristine and functionalised nanomaterials in biological and environmental media in vitro and in vivo, as well as describes brief methods for measuring the stability and halftimes of nanomaterials.