A link between chronic inflammation and cancer has been known for well over a century. However, direct evidence detailing the role of inflammation in carcinogenesis has been slow forthcoming. In Hodgkin's lymphoma (HL), a malignancy which has many features reminiscent of chronic inflammation, it is widely believed that Epstein–Barr virus (EBV) plays a role in the pathogenesis of a proportion of the cases. Indeed, this oncogenic virus has been consistently shown to be present in the malignant cells of HL. Furthermore, it is proposed that chronic inflammation, triggered by factors such as EBV, is likely to contribute to tumour cell proliferation, progression and inhibition of apoptosis. A sensitive and reliable method of demonstrating the presence of EBV at the cellular level is, therefore, of particular value when investigating a role for this ubiquitous virus in disease process. In this context, the technique of EBER in situ hybridization described here has become the gold standard for the detection of EBV in histological material.