The Association of Potato Intergenebank Collaborators (APIC) produced a global inventory of wild potato genetic resources that is available on the Internet (www.potgenebank.org/ipd). This database shows that, in many cases, several genebanks have samples of the progeny from a single original germplasm collection. The assumption has been that these samples are genetically equivalent, so all the characterization and evaluation data gathered on a seedlot from one genebank can be applied to all the other "duplicate" seedlots in other genebanks. This assumption was tested by comparing 25 pairs of reputed duplicates in the VIR (St. Petersburg, Russia) and US (Sturgeon Bay, USA) potato genebanks using RAPDs. In 23 of 25 populations, reputed duplicates among genebanks had significantly less similarity than replicate samples taken from a single population. The average genetic similarity of reputed duplicates was 93%, and the lowest was 81%. Thus, users of germplasm should be aware that reputed duplicate populations from these genebanks may not be genetically identical.