The herpesviruses Epstein-Barr virus (EBV) and human herpesvirus 8 and the retrovirus human T-cell leukemia virus type 1 are directly implicated in the pathogenesis of lymphoma and leukemia in man. EBV is associated with an expanding spectrum of lymphomas and it would appear likely that additional, possibly novel, viruses will be implicated in lymphoma pathogenesis in the future. This chapter describes techniques that may be useful in the analysis of viruses and lymphoma including a standard EBV EBER in situ hybridization assay and a degenerate PCR assay for detection of novel herpesviruses. Lastly, a method for analysis of next-generation sequences in the quest for novel viruses is described.