Cotton (Gossypium hirsutum L.) is an important fiber crop in the world. There are about 20 different viruses cause disease on cotton have been found in the world. Cotton blue disease caused by Cotton leaf roll dwarf virus (CLRDV, Genus: Polerovirus, Family: Luteoviridae) is a viral disease of the the most severe damage. In this study, the authors conducted cloning and sequencing of coat protein (CP) gene of blue dwarf virus from cotton in Vietnam, gene size about 606 bp. CP gene sequences isolated from CLRDV in Vietnam have similarities of 98.2 to 99.2 percent compared with the published gene sequences on GenBank.