Epstein-Barr virus (EBV) is associated with the development of lymphoproliferative disorders in the immunocompromised host and in particular post-transplant recipients. The development of a rapid real-time quantitative PCR for the detection of the immediate early gene BZLF1 is described using the Roche LightCycler. BZLF1 codes for the ZEBRA protein, one of the cascade of transactivation factors involved in the lytic life cycle of the virus. The assay is rapid and can detect a single copy of EBV DNA. Intra- and inter-assay variability studies using the external quantitative standards and DNA extracted from whole blood and plasma samples were shown to be within a 0.5 log(10) range.