LONDON, May 15 - Moody's Investors Service has downgraded the foreign currency corporate family, probability of default and debt ratings of Naftogaz Ukrayiny from B1 to B2.

The ratings remain on review for downgrade having initially been placed on review for downgrade on March 11, 2009.

This rating action follows the decision of Moody's Sovereign Risk Group to downgrade Ukraine's sovereign rating from B1 to B2 and to assign a negative outlook to the rating which has a direct impact on the rating assigned to Naftogaz.