A cross-section of sunflower genotypes grown in Australia including commercial cultivars (Suncross 40R, Hysun 33, Hysun 45CQ, Advance, DK3873), breeding lines (Sunfola, S37- 388, PhRR3, HA-R2, MC29, MC69, S37-388RR), wild sunflower varieties (H. annuus, H. argophyllus), a distantly related species (Tithonia diversifolia), and a hexaploid/diploid cross (H. tuberosus L.x H. annuus L.) were assessed for genetic diversity using RAPD (Random Amplified Polymorphic DNA) analysis. A considerable amount of polymorphism was revealed. Of the total of 158 markers amplified, 133 were polymorphic for at least one pair-wise comparison within the 16 genotypes. Overall, 33% dissimilarity was detected, with an average of 27% dissimilarity revealed among the hybrids and breeding lines, which exhibited 38% dissimilarity to the wild varieties H. annuus and H. tuberosus, and 51% dissimilarity to Tithonia and H. tuberosus x H, annuus. PCR of the 5S ribosomal RNA gene spacer region did not reveal any polymorphisms among the cultivated and breeding lines, but did distinguish between H. tuberosus and the other wild species. This survey of a selection of sunflower genotypes indicates that the genetic base of domesticated sunflower may be quite wide. These results suggest that RAPD methodology will provide an efficient tool for the analysis of the sunflower genome, in particular in breeding programs.