Under the auspices of the International Kuril Island Project (1994-2000), a team of Russian, Japanese, and American botanists worked together on all major and most minor islands of the Kuril Archipelago. Despite natural history exploration in the Kurils dating back to 1740, we collected plant specimens on several islands for which botanical information was previously unavailable. The specimens collected during this project, in conjunction with observational and other data collected, support inquiry into the floristics and phytogeography of the region. In addition, the plant materials are being distributed to taxonomic specialists worldwide. The southern islands feature an eastern Asiatic flora strongly influenced by Japan, with spruce and fir forests, dense stands of bamboo, and tall herbs. The flora of the northern islands, more circumboreal to subarctic, exhibits tundra heaths and thickets of pine, alder, and birch. The central islands, with a somewhat depauperate flora, provide a natural laboratory for investigating questions of plant colonization and distribution.