DNA from 46 North American potato (Solanum tuberosum L.) cultivars was examined using the polymerase chain reaction (PCR) with 16 arbitrary primers of 10 nucleotide length (10 mers) to determine the efficiency of randomly amplified polymorphic DNA (RAPD) in delineating cultivars, both sexually derived and clonal variants. The 16 primers yielded 43 useful polymorphisms that were evaluated according to the presence or absence of fragments of equal size. All cultivars were discriminated with as few as 10 primers. The russet sport of Burbank was distinguished from a white-skinned clone by one band. More primers (29) were examined to identify a band polymorphism among six Russet Burbank clonal variants. When the cultivars were grouped by tuber type (excluding the russet clonal variants), three to four primers discriminated these commonly grown cultivars. Determination of cultivar integrity was accomplished with PCR amplification, regardless of tissue source (leaf vs. tuber) for DNA extraction. Cluster analysis based on RAPD markers was performed to examine pedigree relationships of the cultivars. Genetic relationships correlated with some pedigrees; however, many exceptions were noted.