The association between Amyotrophic Lateral Sclerosis or other Motor Neuron Diseases (MNDs) with Lymphoproliferative Disorders (LPDs) and plasma cell neoplasias (such as Hodgkin's or non-Hodgkin's lymphoma, Waldenstrom's macroglobulinemia, multiple myeloma, chronic lymphocytic leukemia) has been described. It is not clear whether LPDs play a role in the pathogenesis of MND; however it is possible that patients might have antibodies against motor neurons. An association between motor neuron disease and Multiple myeloma (MM) is rarely reported in the literature. This article reports a case of a 75-year-old male with MM and MND. Interestingly, the patient was in complete remission for MM when he was diagnosed as MND and he died due to progressive MND.