Mantle cell lymphoma accounts for approximately 7% of adult Non-Hodgkin Lymphomas. It is a neoplasm of monomorphous small to medium-sized B cells with irregular nuclei. The tumor cells express strong IgM and IgD, and B-cell-associated antigens. Nuclear cyclin D1 protein is present in all cases and is the gold standard for the diagnosis. The t(11;14) (q13;q32) in the majority of the cases results in rearrangement of the BCL-1 locus and overexpression of the cyclin D1 gene. Most patients present with disseminated disease. Mantle cell lymphoma is an incurable neoplasm, but it may be treated with different chemotherapy regimen (R-Hyper-CVAD, R-CHOP, bortezomib) and young patients should be considered for high-dose therapy and autologous or allogeneic bone marrow transplantation.