Ukraine's national oil and gas holding company Naftogaz agreed a $300 million loan from the European Bank for Reconstruction and Development (EBRD).
The revolving credit facility will be used to purchase gas to ensure the country has sufficient supplies during winter.
The EBRD's loan to Naftogaz was conditional on the company implementing certain reforms.
Ukraine is in the process of reforming its energy sector to increase transparency, decrease corruption and liberalise a market over which Naftogaz has long had a monopoly.