Technical Abstract: The germplasm collections of the Vavilov Institute of Plant Industry, Russia (VIR) represents the first germplasm made for potatoes, today numbering 8680 accessions of cultivated species. It has tremendous historical and practical importance and a rich history, having been used to document a polyploid series in the cultivars, initial taxonomic hypotheses, studies of interspecific hybridization, and serving as the base for Russian breeding efforts. Despite its importance and size, there has never been a study of its morphological and molecular diversity, and there were many gaps in its passport data. The purpose of the present study is to obtain morphological, ploidy, and microsatellite (SSR) data needed to set up a useful core collection, and to use this collection to study its taxonomy. A core collection initiated from 440 cultivated species accessions and 198 wild species accessions was reduced after an initial evaluation of viability and gross taxonomic identifications to 238 cultivated and 60 wild species. We began evaluations of this core through improvement of a determination of passport data, new chromosome counts, and phenetic studies of morphology and SSRs to determine diversity and taxonomy. The taxonomic studies of the VIR collection of cultivated potatoes are remarkably similar in both morphology and SSRs to prior studies. Our studies showed the need to evaluate the VIR potato collection, as some were dead and misidentified; the new core collection represents a well-characterized subset of the entire collection that is useful for future comparative studies. They also show the reclassify the collection by modern taxonomic methods.