Title: Exceptional del Pezzo surfaces Abstract: A sufficient condition for the existence of a Kahler-Einstein metric on a Fano manifold can be formulated in terms of so-called alpha-invariant of Tian. This invariant can be naturally defined for log terminal log Fano varieties and for a germ of log terminal singularity. Using this invariant we prove the existence of Kahler-Einstein metrics on many quasismooth well-formed weighted del Pezzo hypersurface and compare this result with new obstructions found by J.Gauntlett, D.Martelli, J.Sparks and S.-T.Yau. We apply our technique to classify weakly-exceptional quasismooth well-formed weighted del Pezzo hypersurface using the classification of isolated rational quasihomogeneous three-dimensional singularities obtained by S.S.T.Yau and Y.Yu.