  We show that for every positive curvature Kahler-Einstein manifold in
dimension 2n there is a countably infinite class of associated Sasaki-Einstein
manifolds X_{2n+3} in dimension 2n+3. When n=1 we recover a recently discovered
family of supersymmetric AdS_5 x X_5 solutions of type IIB string theory, while
when n=2 we obtain new supersymmetric AdS_4 x X_7 solutions of D=11
supergravity. Both are expected to provide new supergravity duals of
superconformal field theories.
