This document summarizes Ukraine's energy relations with the EU and some key implications. It notes that 25% of EU gas passes through Ukrainian territory via major Russian pipelines. Ukraine is also the largest consumer of Russian gas. While Ukraine has significant gas transit and storage infrastructure, its energy sector is dominated by the state-owned monopoly Naftogaz. Ukraine joined the European Energy Community in 2010 but has faced challenges implementing reforms to increase competition and integrate its energy market with the EU, with the government retaining significant control over the sector. Overall the document outlines both Ukraine's important role in European energy transit but also obstacles to further energy cooperation between Ukraine and the EU.