This paper presents a lower bound of (D + n/ log n) on the time required for the distributed construction of a minimum-weight spanning tree (MST) in weighted n-vertex networks of diameter D = (log n), in the bounded message model. This establishes the asymptotic nearoptimality of existing time-efficient distributed algorithms for the problem, whose complexity is O(D + n log n). Key words. distributed algorithm, minimum weight spanning tree, lower bound AMS subject classifications. 05C85, 68Q22, 68Q25 PII. S0097539700369740