Baculoviruses were of the first viruses shown to modify the host apoptotic response. Apoptosis is a strictly regulated and evolutionary conserved mechanism by which a cell self-destructs. This condition is characterised by chromatin condensation, blebbing and DNA fragmentation. The process of apoptosis has an important impact on the evolution of the viruses and their strategies of replication. Viruses stimulate apoptosis very early in their replication process, however, baculoviruses have mechanisms that are able to function in the apoptotic pathway and prolong the life of the infected cells until they have completed replication. These viruses have anti-apoptotic genes (iap) and p35 that suppress the activity of the host apoptotic response. In this study one set of iap specific primers was designed to amplify a 450bp internal region of the iap gene. This amplicon was used as a probe to hybridise to the SacI genomic library of Trichoplusia ni single-enveloped nucleopolyhedrovirus (TnSNPV). The initial phylogenetic analysis of this 450bp region of the iap gene suggests that TnSNPV belong to group II baculoviruses.