Epstein-Barr virus (EBV) is the first herpes virus to be completely sequenced. It is implicated in diseases from the benign infectious mononucleosis to malignant nasopharyngeal carcinoma, Burkitt's lymphoma and primary CNS lymphoma in AIDS patients. It has also been found to be associated with some miscellaneous diseases like chronic fatigue syndrome, multiple sclerosis etc. however causality still remains an issue of debate. As the virus mainly targets the lymphomonuclear cells and the reticuloendothelial system of the body, it's various manifestations are often mistaken as leukemic malignancies. We report two such cases of young adults who had been diagnosed as having acute leukemia on the basis of atypical cells in the peripheral blood. One patient later turned out to be a classical infectious mononucleosis and second patient had EBV associated hemophagocytic lymphohistiocytosis syndrome.