The molecular probe data base (MPDB) contains detailed information on synthetic oligonucleotides, including their identification, target genes, applications and bibliographic references. It is available on-line through Internet and can be searched by using Network Information Retrieval tools. In this article the most recent enhancements of MPDB, both in terms of data contents and new ways of access, are described. These include a recently established collaboration with EMBL Data Library, in the sphere of SRSWWW network browser, in view of a better integration of MPDB with other molecular biology databases.