This Windows CD-ROM of the London Dysmorphology Database (LDDB) contains information on 2860 non-chromosomal, multiple congenital anomaly syndromes. There are also 25,529 references. The database is simple to use and the user can browse or search for the syndromes, features and references supplied. Searches can be combined or progressively refined and then printed or saved. LDDB arose from the need to diagnose and provide genetic counselling for the hundreds of rare multiple congenital malformation syndromes. Work began on the database in 1981 with the intention of ascertaining the majority of reported syndromes in the literature. Major reference works were consulted, as well as all journals that might contain a report of multiple congenital anomaly syndromes.