If K is a lattice, then let | denote the lattice of all congruence relations of K. It is known (see [1]) that O(K) is a distributive lattice satisfying some continuity properties (see below). It is natural to ask about the lattice-theoretical characterization of O(K). I f K is finite, then | is also finite, and conversely, every finite distributive lattice L is isomorphic to a O(K) where Kis finite too. This theorem is due to R. P. DILWORTH and is mentioned in [I] without proof. No proof of this theorem has been published as yet. In this note we give a proof of this theorem; some generalizations are also mentioned. Before stating the results some notions are needed. A lattice K is called section complemented if K has a least element 0, and if every x with x_-< y has a complement z in [0, y], i. e. xP, z=O, x U z = y . The length of a chain C o f n + l elements is n, and the length of a finite lattice K is n if K contains a subchain of length n but no subchain of length n + 1.