Co-occurrence of myelodysplastic syndrome (MDS) and plasma cell neoplasm in patients with no history of chemo and/or radiotherapy is rarely reported. Herein, we report a case of a female in her seventieth decade of life who was referred to the hospital for pancytopenia. The patient was asymptomatic and was doing well overall. Serum protein electrophoresis was remarkable for a lambda-restricted monoclonal protein (IgG) estimated at 1.8g/dL. Immunoglobulin G serum level was also elevated, and serum Kappa/Lambda free light chain ratio was decreased. At that time, a bone marrow biopsy showed myelodysplastic syndrome with excess blasts-2 (MDS-EB2) and a monoclonal plasma cell proliferation. Some studies have shown that patients with plasma cell neoplasm could be associated with an increased risk of developing MDS compared to the general population. Based on reviewing the literature, to our knowledge, the pathological mechanism of the co-occurrence of both diseases is not yet clear.