The International Tree-Ring Data Bank (ITRDB) is an invaluable resource, providing access to a massive and growing cache of tree-ring data. Oxygen, carbon, nitrogen and hydrogen isotope tree-ring studies, which have provided valuable climatic and ecological information, have proliferated for decades so an ITRDB expansion to include isotopic data would likewise benefit the scientific community. An international tree-ring isotope databank (ITRIDB) would: (1) allow development of transfer functions from extended isotopic data sets, (2) provide abundant tree-ring isotopic data for meta-analysis, and (3) encourage isotopic network studies. A Europe network already exists, but the international data bank proposed here would constitute a de facto global network. Associated information to be incorporated into the database includes not only the customary ITRDB entries, but also elements peculiar to isotope chronologies. As with the current ITRDB, submission of data would be voluntary and as such it will be crucial to have the support of the tree-ring isotope community to contribute existing and forthcoming isotope series. The plan is to institute this isotope database in 2010, administered by the National Climatic Data Center.