Tensor Hochschild homology and cohomology Claude Cibils D\'ep. de math\'ematiques, Universit\'e de Montpellier 2 Interactions between ring theory and representations of algebras (Murcia), 35--51, Lecture Notes in Pure and Appl. Math., 210, Dekker, New York, 2000. Abstract. We consider the non commutative setting given by a ring A, an A-bimodule M and T the corresponding tensor algebra. We prove that the Hochschild cohomology of quotients T/I by positive ideals coincides with the homology of A whenever the quiver of M has no oriented cycles. If the quiver is an arrow (i.e. T is a triangular two by two matrix algebra) the Hochschild cohomology belongs to a long exact sequence. For other quivers, a spectral sequence converging to the Hochschild cohomology will be described in a forthcoming paper.