During establishment of primary cell culture from the kidney of a dead Pacific white-sided dolphin (Lagenorhynchus obliquidens), a cytopathic effect was observed. Polymerase chain reaction with a set of herpesvirus consensus primers yielded a fragment of the expected size. Nucleotide sequencing of the product indicated that the isolated virus was closely related to an alphaherpesvirus detected in a bottlenose dolphin in the United States, but the sequence identity at the protein level was low (86.6 %). Phylogenetic analysis of the encoded sequence confirmed that the new isolate belonged to the subfamily Alphaherpesvirinae and clustered together with other cetacean alphaherpesviruses. The complete gene encoding glycoprotein B (2,757 bp) was amplified from the novel isolate; the encoded protein was compared with the corresponding protein of other herpesviruses, revealing that this virus belongs to the genus Varicellovirus. Taken together, these results suggest that this virus corresponds to a novel herpesvirus capable of infecting Pacific white-sided dolphins.