Constructed a longitudinal database to examine how basic science departments have been reorganized at U.S. medical schools. Found that there were fewer basic science departments in the traditional disciplines of anatomy, biochemistry, microbiology, pharmacology, and physiology in 1999 than in 1980. But as biomedical science has developed in an interdisciplinary manner, new basic science departments have been added. The most frequent type of change was the renaming of existing departments. (EV)