This study attempts to characterize three species of Euphorbia (Euphorbia prostrata Aiton, Euphorbia peplus L. and Euphorbia terracina L.) grown in Abha area, Aseer region, Saudi Arabia and determine the genetic polymorphism among them by using the two DNA markers: randomly amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) by polymerase chain reaction (PCR). Total genomic DNA of studied species was extracted from fresh leaves by using the DNeasy plant mini kit. Molecular analysis was performed by using 12 RAPD primers namely oligo203, oligo345, oligo42, oligo349, oligo213, oligo33, oligo211, OPJ-1, OPE-18, OPJ-5, D07 and OPM-7 and 10 ISSR primers namely Primer 4, Primer 3, UBC888, UBC840, UBC826, UBC824, UBC842, ISSR06, Primer 1 and Primer 2. PCR amplifications with 12 RAPD primers gave 151 scorable bands, out of which (21.50%) were found to be polymorphic, (4.63%) monomorphic and unique bands for E. peplus (15.89%), for E. prostrata (21.57%) and for E. terracina (28.04%). Primers OPJ-5 and OPM-7, generated the highest number of bands while the lowest number of bands was obtained from primer oligo42. Generated dendrogram using Ward's linkage method to cluster the data revealed...