Mantle Cell Lymphoma (MCL) is associated with a dismal prognosis. Recently, along with the improved understanding of the pathophysiology of this disease, new first line regimens have been established and in addition novel treatment options have entered the clinical arena. In consequence, prognosis of the disease has fortunately improved. We here focus on the rationale, current clinical knowledge and future concepts of Temsirolimus, an inhibitor of mTOR, in the treatment of MCL. At this time this drug has been shown to be effective as single agent for relapsed disease and early combination data show promising results. In addition, with a brief outline of other treatment options, we aim to guide at which place in the current treatment algorithms Temsirolimus can be integrated into the treatment of MCL patients.