Grapevine leaf roll-associated virus 3 (GLRaV-3) is one of the most important viral diseases of grapevine in the world. In this study, GLRaV-3 Ampelovirus was identified from grapevines in Korea by analyzing viral coat protein size, nucleotide, and amino acid sequences. The molecular weight of viral coat protein from virusinfected in vitro plantlets was determined by western blot using a commercial GLRaV-3 polyclonal antibody. Western blot analysis showed a coat protein of about 43 kDa. RT-PCR product of about 942 bp which encoded the coat protein (CP) gene was amplified with specific primers. When the viruses existed at low titers in the host plant, the dsRNA had very specific template in RTPCR amplification of fruit tree viruses. Especially, small-scale dsRNA extraction method was very reliable and rapid. Sequence analysis revealed that the CP of the GLRaV-3 Ko consisted of 942 bp nucleotide, which encoded 314 amino acid residues. The CP gene of GLRaV-3 Ko had 98.9% nucleotide sequence and 98.7% amino acid sequence identities with earlier reported GLRaV-3. This is the first report on molecular assay of GLRaV-3 Ampelovirus identified from Korea. The GLRaV-3 Ko CP clone would be very useful for breeding of virus resistant grapevines.