The goal of the current study was to evaluate the molecular diversity in adults of the spiny bollworm Earias insulana that irradiated with doses of 25, 50, 100, and 200Gy as full-grown pupae. Data from ISSR-PCR showed that the DNA bands of the groups under study varied. According to the similarity index, the control adult pupae had a low similarity index to the other irradiated adults (as full grown larvae). In this investigation, six primers of uninformed sequences were tested to check genomic DNA of the E. insulana adults. The molecular weight varied between 145 bp to 1435 bp. In the current search, irradiated adults were contrasted to unirradiated ones to explore any potential changes to the DNA structure that might be a result of gamma radiation treatments. The obtained results showed polymorphic, monomorphic and unique bands in the fingerprints generated in adults resulted from gamma irradiated full grown when compared with normal adults. Moreover, the highest numbers of amplified bands were 8 generated from primer HB13, whereas the lowest numbers of amplified fragments were 3 detected from two primers 49B and HB8 in gamma irradiated adults as pupae. The resulted ISSR-PCR patterns using primer HB10 revealed the lowest value of similarity index (0.33) between irradiated adults “as full grown pupae” with 50Gy and the unirradiated adults which displays the greatest degree of alteration in DNA sequence and arrangement.