Implementing the concept of sustainable development is one of the major challenges facing the modern world. One of the instruments creating sustainable development might be state aid. State aid has an impact not only on the economic sphere but also the environmental and social. State aid can have beneficial, negative or neutral impact on the implementation of sustainable development. The impact of state aid should be considered including the three spheres: economic, social and environmental. The main objective of this article is to try to identify tools and approaches that can be used to examine the impact of the measure state aid for sustainable development and to show which state aid is detrimental to sustainable development. The article presents such instruments and give its in-depth describe. The article consists of three main parts. The first part shows state aid in the concept of sustainable development. Another part shows which state aid can be regarded as harmful to sustainable development. The third part presents the tool with which we can identify harmful state aid.