Abstract: This study was conducted to identify White Spot Syndrome Virus (WSSV) and Infections Hypodermal and Hematopoietic Necrosis Virus (IHHNV) by using clinical and histopathological sings of cultured shrimp, Litopenaeus vannamei in Bushehr farms, from December 2009 to April 2010. Samples were collected from Bushehr shrimp farms and hatcheries. Based on histopathological and gross signs, two viral diseases, WSSV and IHHNV have been detected. The gross signs of WSSV in the moribund samples showed reduced feeding, lethargy, difference in size, reddish coloration of appendages and white plaque on the carapace, while the gross sign of IHHNV exhibited abdominal dorsal changes of the muscles, opaque or milky spot on the cuticles, rostrum deformity syndrome and abdominal segmental abnormalities. The histopathological observations of WSSV showed basophilic Cowdry type A inclusion bodies in all tissues such as gills, haematopoietic tissue, cuticle epithelium, lymphoid organ and connective tissue. However, histologically, the hepatopancreas tissue showed vacuolization of B cells, without inclusion bodies. The histopathological signs observed such as hypertrophy, cellular degeneration and eosinophilic Cowdry type A inclusion bodies in the cells nucleus hepatopancreas, gills, haematopoietic, cuticle epithelium, digestive epithelium, lymphoid organ and connective tissue. Also, histopathological change of the striated muscles of the affected abdominal segmental abnormality showed severe Zenker's necrosis.