The all-pairs-shortest-length (APSL) problem of a graph is to find the lengths of the shortest paths between all pairs of vertices. In this paper, we study the APSL problem on chordal bipartite graphs. By a simple reduction, we show that solving the APSL problem on chordal bipartite graphs can be transformed to solving the same problem on certain strongly chordal graphs. Consequently, there is an O(n(2)) time-optimal algorithm for this problem. (C) 1999 Elsevier Science B.V. All rights reserved.