Safflower (Carthamus tinctorius L.) is a herb primarily distributed throughout in the world. We have used the inter-simple sequence repeats (ISSR) technique to investigate the phylogenetic relationships and genetic diversity of C. tinctorius. Of all germplasms, 88.7% were polymorphic among all germplasms. Mean genetic diversity within germplasms was very low (0.048). The Turkey germplasm had the highest expected diversity (0.082) and Australia germplasm was the lowest (0.020). These values indicate that most of the genetic diversity of safflower is found among germplasms and there is a high among-germplasm differentiation. We found eight phenetic bands for determining the specific marker of germplasm with SCAR markers. The regions of the Mediterranean Sea and India may be the most probable candidates for the origin of safflower. The tree showed four major clades: (1) European germplasms, (2) Azerbaijan, Egypt, and Ethiopia, (3) Australia, and (4) America.