110 isolates of Beauveria (104 B. bassiana, 5 Beauveria spp., 1 B. brongniartii) were obtained from Sunn Pests (Eurygaster and Aelia species), litter, and other insect samples at overwintering sites in seven countries in the Middle East and West Asia. DNA was extracted from these isolates, and four techniques were used to characterize and to investigate genetic diversity at the molecular level: ITS-RFLP, ITS sequencing, ISSR-PCR, and AFLP. The ITS-RFLP and ITS sequences did not detect significant genetic variation among the isolates. However, both ISSR-PCR and AFLP analyses gave indications of intraspecific groupings correlated with geographical origin and relative genetic diversity among some isolates, but no obvious association with Sunn Pest hosts. There was no obvious genotypic grouping of B. bassiana isolates from E. integriceps, perhaps suggesting the overwintering populations were infected by generalist native isolates rather than by host-specific ones that might be more suitable for biocontrol purposes.