Ruthenium benzylidene metathesis catalysts react with 2,3-dicarbomethoxymethylene-cyclopropane, eliminating styrene and dimethyl fumarate, and producing the first terminal ruthenium carbide complexes. The products are diamagnetic, air-stable, and moderately soluble in hydrocarbon solvents. An X-ray study of Ru(C:)Cl2(P(C6H11)3) (1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) shows a Ru-C distance of 1.650(2) A, consistent with the presence of a very short Ru-C triple bond.