As cryptocurrencies are becoming more and more widespread and their power consumption has caught the attention of the public, it seems worthwhile to investigate their effects on the environment, economy and society. In the scientific literature, a clear focus on the high power consumption of the market-dominating Bitcoin can be seen in the sustainability assessment of cryptocurrencies. In order to build a comprehensive understanding of cryptocurrencies’ sustainability other aspects should be considered as well instead of narrowing down the scope of analysis to power consumption. Therefore, a holistic definition of sustainability in the context of cryptocurrencies is proposed. Building upon this definition a methodology for assessing a cryptocurrencies’ sustainability is derived in this paper and subsequently applied to ten cryptocurrencies.