Hyphantria cunea is a fall webworm is considered an agricultural pest. It is a major pest of many board-leaved trees. H. cunea nucleopolyhedrovirus (HcNPV) and H. cunea granulovirus (HcGV) were isolated from the fall webworm cadavers in Korea. To better understand HcNPV and HcGV, their genomic sequences were determined, analyzed and compared to two viruses together. The entire nucleotide sequence of the HcNPV genome was fully sequenced using 454 pyrosequencing. The genome of the HcNPV was 131,302 bp with a 45 % G+C content. Computer assisted analysis predicted 146 open reading frames (ORFs) of 50 or more amino acids that showed minimal overlap. Further more, when the phylogenetic relationship was analyzed, HcNPV was closely related to Orgyia pseudotsugata MNPV (OpMNPV) which belong to Group I NPV. The HcGV genome was 114,557 bp with a 39% G+C content and contained 130 putative ORFs of 50 or more amino acids. When phylogenetic relationships were analyzed, HcGV was closely related to Xestia c-nigrum granulovirus, which belong to the Type-II GV. HcNPV shares 48 ORFs with HcGV. The most significant difference between HcNPV and HcGV is fgf gene. HcNPV contains one fgf gene, whereas HcGV contains three fgf genes. The presence of fgf reduces the time and efficient systemic infection it takes the virus to kill its host. The difference of fgf number from HcNPV and HcGV suggested that different affect for the speed of systemic infection.