Cucurbit aphid-borne yellows virus (CABYV) was reported for the first time as a tentative new member of Luteovirus group and one of the most prevalent viruses infecting cucurbits in France . This virus causes yellowing and thickening of the older leaves in infected plants. In this study, cucurbits including cucumber ( Cucumis sativus L.), Melon ( Cucumis melo L.), Squash ( Cucurbita sp.), Watermelon ( Citrullus lanatus L.) and weeds showing yellowing and thickening of the older leaves and symptomless samples were collected from cucurbit fields in Isfahan and Hormozgan provinces. Total RNA of leave samples was extracted and used as template in RT-PCR. RT-PCR was preformed using CABYV specific primers (CABYVGF and CABYVGR). Expected size amplification of 484 bp in some samples of squash, cucumber, and melon and weed species of Chenopodium album , Plantago major and Sinapsis arvensis confirmed their infection to CABYV. For amplification of full length of CABYV coat protein (CP) gene, two overlapping expected sizes of 484 bp (amplified using CABYVGR and CABYVGF primers) and 479 bp (amplified using CABYVBR and CABYVBF primers) were amplified in two isolates named Agha-Ali-Abbas and Rudan. The PCR products were cloned and sequenced. The BLAST search showed high similarity between nucleotide sequences of Agha-Ali-Abbas and Rudan isolates and other CABYV isolates available at GenBank. Two overlapped sequences were assembled to construct full length of CP gene. Comparison of deduced amino acid sequences of CP gene of Agha-Ali-Abbas and Rudan isolates with those of other CABYV isolates revealed the highest (98.4% and 98.9%) and the lowest (90.2% and 90.7%) similarity with pM0911-2 and 37-5 isolates of CABYV, respectively. These results were confirmed by phylogenetic analysis based on amino acid sequence of CP gene. In transmission test, Aphis gossypii transmitted CABYV to Cucumber. The infection of Cucumber plants was confirmed by RT-PCR