A 50-year-old male presented with cough and breathlessness. A positron emissoin tomography scan revealed FDG (Fluorodeoxyglucose) avid mediastinal mass. Tru-cut biopsy showed fibrotic stromal tissue with cellular infiltrate consisting of abnormal lymphoid cells and few large cells with smudged nucleus. Immunohistochemistry revealed diffuse positivity with CD20, focal positivity for CD30 and rare CD15 positive cells. Histological picture and immune profile showed overlaping features of non-Hodgkin's as well as Hodgkin's lymphoma. A diagnosis of mediastinal gray zone lymphoma was made. The patient showed a complete metabolic response to six cycles of chemotherapy.