To examine the genetic similarity of cotton cultivars available in Australia, twelve cultivars of Gossypium hirsutum, together with an American Pima cotton (G. barbadense) cultivar, were subjected to genetic fingerprint analysis using the technique of RAPD-PCR 1 The study revealed that it is possible to differentiate each of the CSIRO cultivars, even though the majority of these cultivars possess greater than 90% of their genetic material in common (Figure 1 ). As would be expected from their wide pedigrees, cul ti vars such as CS 50 and DP 90, together with the G. barbadense cultivar Pima S-7. reveal much less genetic similarity. From these results we can assume that if such an analysis were extended to cultivars with unknown pedigrees, it would be possible to obtain a detailed picture of their genetic relatedness.